OK, so one extreme would be B/X D&D, lets say, where you just pick one of 4 or 5 classes/races and besides that you've got your equipment, and maybe spells, plus ability scores. I expect if we assume a 'put them in any order' on the ability scores, then you can build, at very low-fi, whatever character you envisage.
B/X was explicitly roll in order, with a limited option to drop two points from a non- dex, con, or cha stat (but not below a 9) to bump up your prime requisite by 1. Unlike AD&D it offered no RAW alternatives that can shape more to a predetermined priority of stats.
For the most part though I think stats are fairly irrelevant and you can roleplay most any personality and approach with any stats or class so I big picture come out to the same point as you. You want a Sean Connery James Bond approach B/X elf? It will work fine. Whether it will get successful results will depend entirely on the player's specific approach in the situation and the DM's adjudication.
You will run into problems with things like "Conan has all 18s" or some such with certain character concepts/ability score rolls, but that is maybe more a question of 'score inflation' than an actual problem with that system.
4e would kind of be the other extreme where you have tons of classes, MCing, hybrids, loads of feats, background, theme, and PP/ED, as well as proficiencies and power selection. As long as your concept isn't broken by some small detail of how your powers work or whatnot then you should be able to build something that's pretty expressive of the concept. It has the virtue over the B/X version of having a lot of 'hooks', but OTOH that also means mechanics are going to 'hook' you and that might not be what you want! Still, things like the Lazylord, for example, can be pulled of, which is kinda cool.
Personally I've built some pretty distinctive characters at both extremes, but then I'm not generally in the same sort of mindset as some of the more 'OC' people who want something very exactly a certain way. So, build options were never really, in and of themselves, something that either draws me to or repels me away from a system (though I admit, I can imagine there being too little, but still early D&D can be enough).
Well, I'm not ENTIRELY sure why Fate is the opposite pole there. I mean, maybe kinda sorta, but it depends perhaps on what you value in 'character stuff'? Like, 4e SUBSUMES what Fate does, in a sense, AND gives you loads of detailed mechanical stuff. I think of every item on the character sheet as both a mechanical unit of stuff and as a free descriptor! I also think that Original D&D meant its ability scores in much more of a free descriptor way than is now commonly understood. Like, in the original core 3 books there's ALMOST no rules associated with ability score (there are a couple, I think CON and DEX have some actual effects, and there's the prime requisite rules). Why is it good to be a strong fighter in that system? Because you can SAY "I'm strong, therefore..." Now, its true that bonuses got added pretty quickly, but it was still the case in a lot of AD&D play (ours for instance) that you could use ability scores, or class, or race, like a free descriptor and ask for stuff. Obviously Fate codifies all that!
Here I diverge. I think the lack of stuff in the older rules is not an indication that stats should be narrative guides to empower or limit stuff in games. I just took stats as things with a very few defined mechanical impacts.
Generally I think there was a lot of variation on this sort of stuff between individuals and groups.
I looked at B/X for instance and saw the intelligence score as describing prime requisite stuff and bonus languages known and that was it. I expected remembering stuff in actual play to be a player aspect and not something impacted by the stats for a DM gimme or a roll even with the B/X description of intelligence as the ability to remember knowledge.
So, I was discussing 4e vs B/X in more "what mechanical tools are there" because from my perspective they're all equal in the descriptors space (and then in that sense Fate IS the opposite of all D&Ds since it centers the mechanics on that descriptor thing, and gets rid of a lot of the other stuff).
Anyway, at the very least there are several dimensions in this space.
I see 4e as much more descriptor leveraging oriented. The skill system explicitly says to use trained skills to narratively empower cool cinematic thematic open ended moves. B/X has nothing explicitly similar. B/X says nothing one way or the other about whether your character can be an acrobatic anime ninja. 4e does.
I'm not sure how 'ad hoc' ability scores are in older D&D. Think of it this way. I have an INT of 15, that's roughly a 148 IQ. You ARE A GENIUS, not just 'kinda smart', and you can definitely play with that. Granted, old school D&D is not going to give you a formal label to put on your character "Scholar of Middle Cardolan History" to leverage, but there was a VERY active school of classic D&D that was doing this sort of stuff by 1976 at the latest. My point is, it isn't exactly subverting the rules, or even adding any new ones. Its more just 'how do interpret and adjudicate'. If "less rules/FKR whatever" means anything, then that's where it lives!
That is not a B/X description of a 15 intelligence.
Here is the sum total of the B/X intelligence description:
"Intelligence: "Intelligence" is the ability to learn and remember knowledge, and the ability to solve problems. Characters with an intelligence score of 13 or above should consider the classes of magic-user or elf. Intelligence is the prime requisite for magic-users, and one of the prime requisites for elves."
Intelligence:
Intelligence Score Use of Languages
3 Has trouble with speaking, cannot read or write
4-5 Cannot read or write Common
6-8 Can write simple Common words
9-12 Reads and writes native languages (usually 2*)
13-15 Reads and writes native languages, + 1 added language
16-17 Reads and writes native languages, + 2 added languages
18 Reads and writes native languages, + 3 added languages
* Humans know two native languages: the Common and Alignment languages (see Languages, page B13). Demi-humans know a number of native languages, as explained in the class descriptions (pages B9-10).
I view the less rules/FKR style as more just play the role you want without mechanics, not to use poorly defined mechanics as hooks for ad hoc mechanics.
More anybody can play most anything within whatever the assumed baseline is, not using stuff on the sheet to empower or limit actions.
The old games do not make stats as descriptors a baseline, though it is not precluded as an option for how a DM will adjudicate a situation.
Some used stats as descriptors. Others used the stats as their defined mechanics only.