When I said limitation it was because nowadays with computers you can sort let it figure some of that stuff out for the players and back then it pretty much had to be done by hand and all figured out ahead of time. Now you can still have all the stats and do everything as before (Obviously not in Skyrim, but if devs do build such a game...) and that's fine too.
Again, I will say that I don't know exactly what you mean. On the surface I would say that that is not (and was not) the case, but I'm not sure of what you mean.
I can say that it's nuts to have a stat system and not allow the player to know what they are; they have to know in order to play (and how not to play) as the character.
There is not a technological limitation here; PCs are great with numbers, and stats are nothing compared to even 4 bit graphics.
Which is a limitation of the game engine and how and how Bethesda implemented the characters and AI not really because of the character system.
I disagree because the character system defines how the game agrees or disagrees with the player, on matters of the character. The AI is tertiary, and could be replaced with a pop up that says that they beat the hell out of the PC.
(And be done statistically.)
Because it still is totally within your power to still choose what skills you use and how your character plays as you go along. Sure if you never put any thought into it all then you probably won't be able to distinguish your own character that you made, but otherwise yeah, it should be easy to distinguish and define what's in or not in character. (With obvious exceptions to how the NPCs and game world is designed. But that's always true since devs never plan or implement all possibilities.)
Fallout allowed the PC to define aptitudes, and start out proficient in something; even FO3 retained a sliver of this.
The only game that I have seen to do 'learn by doing' well, was Lands of Lore:Throne of Chaos; and even then the PCs all had lives leading up to the start of the game, and begin the game as very competent in one area, or reasonably competent in several.
** I would be open and look forward to a Lands of Lore sequel by Bethesda. I might also like their take on a the Palladium Books RIFTS setting. These kind of suit them, where Fallout does not.
*** Incidentally, Lands of Lore:ToC was a first person dungeon crawler with fully voiced PC dialog, and a lot of it; made in 1994; just around the time that development of Fallout was begun.
****Incidentally again... Two years before Fallout, Interplay's big game was a first person adventure with a spell casting, sword wielding warrior, and was fully voiced, and had dual wielded weapons that hit where you targeted. It's called Stonekeep.