An interesting note is that Classic Traveller's skill system is closer to D&D 3E Feats or ACKS Proficiencies than to later Traveller Skills of D&D 3E Skills. In many cases, outside weapon specializations ("weapon skills"), the skill level matters less than whether or not you have the skill.
I look at it another way. I call it the "inclusive" vs "exclusive" skill approach - if it's not listed on my character sheet, can I do it anyway, even if not well? Yes (inclusive) or no (exclusive)?
Advanced Dungeons & Dragons 1st ed, as a class-based system, did not cover many more mundane things like "can you tie a knot?" or "can you trap a rabbit?" This is for cultural reasons: as the saying goes, the past is a different country, they do things differently there. When Gygax wrote AD&D in the late 1970s, and certainly when he had his childhood years before, essentially everyone could ride a horse, pitch a tent, cook dinner and so on. No roll was needed because, "yeah, of course you can do that."
There was a level of assumed competency. This was inclusive.
As time went on more and more people lived in urban settings with airconditioning and TV dinners and so on, and this competency could not be assumed. The default went from "yes you can do that (because after all, everyone can)" to "no, you can't do that (because after all, most people can't)". Thus the skill system in AD&D 2nd edition and of course later editions. The game designers couldn't start a fire or ride a horse, so they assumed that characters in a medieval fantasy setting couldn't, either - unless it was written on their character sheet. This was exclusive.
This was compounded by computer games, where character development was commonly in terms of skills. The computer game designer had two options, either to make the skill development closed ("100% now, maxed out") or open ("sure, you can have 150% lockpicking... and do "impossible (-100% to roll" locks!". Now, that's all well and good, but of course since you need only yourself to play computer games, you can play them for many more hours than you can tabletop RPGs. This led to the "drop-down menu effect" at game tables, where the DM would say, "Now what do you do?" and the players looked down at their character sheets, mentally dropping down the menu of applying Skill X to Problem Y - where in previous years, players would look around the table at other players for suggestions.
Let us not give into silly communist ideas that "there's no wrong way to play." Tabletop roleplaying games are a social creative hobby, and therefore we must take approaches which encourage both sociability and creativity.
A game system where, "if it's not listed, you can still do it, even if not well, if it's listed then you can do it well," encourages sociability, since it avoids the "drop-down menu effect". A system which errs on the side of the simple takes the creativity which the rules-lawyer/power-gamer dual-classed player would have applied to minimaxing, and has them apply that creativity to play.
Obviously there are other things to consider, too. There's a difference between, "Even if not listed, you can do it" with a roll of 20 on d20 vs 10. Likewise with +0 as the default and +1 as the first skill level, vs +0 and +5. And of course there may be other considerations like taking extra time, using equipment and so on. And perhaps having the skill is a prerequisite for using the assisting equipment at all. And some kills like horse riding might be available to everyone, and others like flying a jet fighter only to those with training.
But when in doubt, before considering realism or being true to the genre or what-have-you, I would choose whichever approach encourages creativity and sociability at the game table. Because that's where the fun is.
Of course, you may choose a different approach. But you're wrong.
An example of a "permission" that I find very satisfying is the Knowledge proficiency in ACKS. You have to choose a subject for that knowledge, but you can choose whatever you like. This lets you, as a player, respond to your own understanding about the game world by taking something that is setting-aligned. But it also gives you the opportunity to bring something strange and new into the setting.
The FATE system, with its back-and-forth jockeying (i.e. Compels vs. Aspects) feels like a dice-driven storyteller system to me more than an RPG. It's very socially driven, with everyone at the table being hyper-aware of the Aspects in play and most of the action consisting of riffing and improv around those Aspects.
The game world/setting does not achieve the same level of coherence as something with a strong implied setting, and the level of play I would describe as more cinematic and party-focused rather than something like exploration or worldbuilding.
For me, the most satisfying aspect of RPGs is that a character can leave a substantial mark on a living setting. That requires a devotion to or elevation of the setting that FATE, with its semantic-focused narrative construction, downplays for player-character focus.
It is a very interesting system, but the way it uses its skill system is very different from how the same would operate in e.g. D&D because the implications for success and failure in D&D can apply to other characters, parties, or time periods in a more causally distinct way since Fate Points or other mechanisms cannot simply "rewrite history."
The farther a skill system gets from "list of ideas with number next to them" the better.
The closer a skill system gets to "these are actually just class traits" the better.
It sounds like BoL is much closer to the 2nd design. Thieves in AD&D and BX and so on have a "skill list" which is restricted to their class and is more of an expression of "behaviors and abilities that this type of person would naturally excel at." I really like that design because it excludes other classes from trying to do those things. Negative space is highly informative and clarifies a lot of uncertainties.
An interesting note is that Classic Traveller's skill system is closer to D&D 3E Feats or ACKS Proficiencies than to later Traveller Skills of D&D 3E Skills. In many cases, outside weapon specializations ("weapon skills"), the skill level matters less than whether or not you have the skill.
I look at it another way. I call it the "inclusive" vs "exclusive" skill approach - if it's not listed on my character sheet, can I do it anyway, even if not well? Yes (inclusive) or no (exclusive)?
Advanced Dungeons & Dragons 1st ed, as a class-based system, did not cover many more mundane things like "can you tie a knot?" or "can you trap a rabbit?" This is for cultural reasons: as the saying goes, the past is a different country, they do things differently there. When Gygax wrote AD&D in the late 1970s, and certainly when he had his childhood years before, essentially everyone could ride a horse, pitch a tent, cook dinner and so on. No roll was needed because, "yeah, of course you can do that."
There was a level of assumed competency. This was inclusive.
As time went on more and more people lived in urban settings with airconditioning and TV dinners and so on, and this competency could not be assumed. The default went from "yes you can do that (because after all, everyone can)" to "no, you can't do that (because after all, most people can't)". Thus the skill system in AD&D 2nd edition and of course later editions. The game designers couldn't start a fire or ride a horse, so they assumed that characters in a medieval fantasy setting couldn't, either - unless it was written on their character sheet. This was exclusive.
This was compounded by computer games, where character development was commonly in terms of skills. The computer game designer had two options, either to make the skill development closed ("100% now, maxed out") or open ("sure, you can have 150% lockpicking... and do "impossible (-100% to roll" locks!". Now, that's all well and good, but of course since you need only yourself to play computer games, you can play them for many more hours than you can tabletop RPGs. This led to the "drop-down menu effect" at game tables, where the DM would say, "Now what do you do?" and the players looked down at their character sheets, mentally dropping down the menu of applying Skill X to Problem Y - where in previous years, players would look around the table at other players for suggestions.
Let us not give into silly communist ideas that "there's no wrong way to play." Tabletop roleplaying games are a social creative hobby, and therefore we must take approaches which encourage both sociability and creativity.
A game system where, "if it's not listed, you can still do it, even if not well, if it's listed then you can do it well," encourages sociability, since it avoids the "drop-down menu effect". A system which errs on the side of the simple takes the creativity which the rules-lawyer/power-gamer dual-classed player would have applied to minimaxing, and has them apply that creativity to play.
Obviously there are other things to consider, too. There's a difference between, "Even if not listed, you can do it" with a roll of 20 on d20 vs 10. Likewise with +0 as the default and +1 as the first skill level, vs +0 and +5. And of course there may be other considerations like taking extra time, using equipment and so on. And perhaps having the skill is a prerequisite for using the assisting equipment at all. And some kills like horse riding might be available to everyone, and others like flying a jet fighter only to those with training.
But when in doubt, before considering realism or being true to the genre or what-have-you, I would choose whichever approach encourages creativity and sociability at the game table. Because that's where the fun is.
Of course, you may choose a different approach. But you're wrong.
My favorite type of skill system gives a character “permission” to make a new and interesting kind of decision in the game world.
Anyone can drive a car, a pro driver can attempt advanced stunts *and* has a +4 on their normal drive checks.
FATE got this one right with permission aspects and talents letting characters use the same core skill set in new ways.
An example of a "permission" that I find very satisfying is the Knowledge proficiency in ACKS. You have to choose a subject for that knowledge, but you can choose whatever you like. This lets you, as a player, respond to your own understanding about the game world by taking something that is setting-aligned. But it also gives you the opportunity to bring something strange and new into the setting.
The FATE system, with its back-and-forth jockeying (i.e. Compels vs. Aspects) feels like a dice-driven storyteller system to me more than an RPG. It's very socially driven, with everyone at the table being hyper-aware of the Aspects in play and most of the action consisting of riffing and improv around those Aspects.
The game world/setting does not achieve the same level of coherence as something with a strong implied setting, and the level of play I would describe as more cinematic and party-focused rather than something like exploration or worldbuilding.
For me, the most satisfying aspect of RPGs is that a character can leave a substantial mark on a living setting. That requires a devotion to or elevation of the setting that FATE, with its semantic-focused narrative construction, downplays for player-character focus.
It is a very interesting system, but the way it uses its skill system is very different from how the same would operate in e.g. D&D because the implications for success and failure in D&D can apply to other characters, parties, or time periods in a more causally distinct way since Fate Points or other mechanisms cannot simply "rewrite history."
What about career/profession based skill systems like barbarians of lemuria?
Where your 'career' lets you roll for a range of 'skills' that fit within that profession?
The farther a skill system gets from "list of ideas with number next to them" the better.
The closer a skill system gets to "these are actually just class traits" the better.
It sounds like BoL is much closer to the 2nd design. Thieves in AD&D and BX and so on have a "skill list" which is restricted to their class and is more of an expression of "behaviors and abilities that this type of person would naturally excel at." I really like that design because it excludes other classes from trying to do those things. Negative space is highly informative and clarifies a lot of uncertainties.