I wouldn't even know where to start creating a rule system that would work for absolutely every build. In dice games there is a GM present to do all the scaling using his brains, common sense, and player evaluation to do the monster selection etc. No simple algorithm in the world can make such thought out decisions.
Maybe an anolytical evaluation of the progress is more sensible for the future? However, that too would be exploited to the death and called "too simple". Like, did the player just one-shot a bandit while not being affected by good role playing (using his tricks)? If so, maybe up the challenge for the next fight. This is how a game master thinks, but hard as hell to implement as a generalized system that also wants to appear fairly static to the players.
At level 45 master, although I sometimes find it a bit too easy for my current build, at least it's up there where it should be, where fights are still fast and furious (winning or loosing aside), rather than the hour long fights from Oblivion.
So far, I say well done Bethesda - much improved from last time(s). Not ultimate perfection, but I don't believe that is feasible, but feel free to prove me wrong

It was overpowered by making it look ridiculous and not taking into account other stuff (such as your current weight etc). If skill didn't matter that much and you had to sacrifice perk points to get to the really good stuff, it would limit itself to the builds that required it. For me, these sorts of skill make a lot of sense, but Oblivion just had it badly implemented since you could become master of all skill and access all benefits.