In Morrowind, Galsiah's Character Development and MADD Leveler made skill and attribute increases happen gradually as you used the relevent skills. In Oblivion, nGCD and Kobu's did pretty much the same things. In a few of them, the skills affected one "controlling" attribute more than the others, but several received smaller increases. I recall swinging a Longsword and seeing my Personality attribute go up a point at one time (kind of an extreme example). I think that may have been "stretching" things a bit, but I can see where using a weapons could (and probably SHOULD) cause small increases to Speed, Endurance, and Agility, as well as the obvious and larger Strength boost. The existing system of skills and attributes is great, but the current way they're increased at level-up when you sleep, with "multipliers", could use some help. Bethesda should at least give those levelling mods a good look.
Beyond that, the "hard cap" of skills and attributes at 100 made all characters begin to turn into the same "clone" hero at high levels. Beyond 100, the rate of skill increases should be at least 4X as hard, or get progressively slower at each 10 points over 100, so 110 would be quite possible in one or two skills and attributes, but 150 would be somewhere between amazing and impossible. Maximum limits might well be affected by one's initial choices, so you could have the "potential" to go above 100 on your Major skills by making the most of your inborn abilities, but not on Minors where you're starting with an inherent weakness. I also don't mind seeing a couple of specific "perks" for quest rewards by certain factions, or as "one time" choices between two or three possibilities (a character could only get ONE of them), so one character would be "different" from another due to the course they chose. Late-game characters need to maintain some distinctiveness, and "automatic perks" like in OB don't do that, because EVERYONE gets them at those same skill levels. "Plentiful" perks as in FO3 cheapen and in many cases bypass the basic skill and attribute system, turning normal character advancement into nothing more than a waste of programming. The SPECIAL system in FO3 was fine, it's just that the game hardly used it.......