Well said! The level scaling is ok in TES2 and 3, but huge fail in TES4. So, don't get RID of the level scaling, just make it better.
The reason I say scaling is a bad idea is that it disables any real tangible effect of leveling; when I turn level 20, I want to kill the rat in one hit, even if I'm slapping it with my bare hand. It's a
rat. Enemies later in the game, however, like daedra and trolls, should be harder to kill, requiring better skills and higher level to engage them. This mechanic can be used to open the world more slowly, as a reward for leveling and improving skills. This, coupled with the inability to fast travel to cities without first walking there, would make the game world seem larger, since there would be a progression to the game world opening up. The final thing this allows for is unique artifacts, ones that don't level as you level. There could finally be "best weapons in the game" that are worth going after, and high level and great skills would be necessary to acquire them. Even accessing the areas where these weapons are found could require high skills, like high destruction skill to annihilate a magical barrier to some new area.
As for the key class skills idea, I think I have a decent start: we already have skill sets that contain related skills: Combat skills, Stealth skills, and Magic skills (referring to OB manual). When you create a class, you have the ability to choose one skill from each skill set, which will affect the rate at which the levels of other skills increase from those skill sets. Basically, there is one other "aligned" skill for each key skill you choose, and one "degenerate" skill. Every other skill in the sets are unaffected by your choice. A rough sketch of how this should go, in order of key class skill, aligned skill, degenerate skill:
Combat skills
block, blade, hand-to-hand; armorer, heavy armor, blunt; heavy armor, blunt, athletics; blunt, athletics, armorer; blade, block, hand-to-hand; athletics, blade, block; hand-to-hand, athletics, heavy armor
Magic skills
destruction, alteration, illusion; alteration, illusion, mysticism; illusion, mysticism, alteration; conjuration, destruction, restoration; mysticism, illusion, alchemy; restoration, alchemy, conjuration
Stealth skills
Security, sneak, mercantile; sneak, marksman, acrobatics; acrobatics, light armor, speechcraft; light armor, marksman, security; marksman, sneak, speechcraft; mercantile, speechcraft, marksman; speechcraft, mercantile, security
There's also the possibility that the player can choose a key skill, aligned skill, and degenerate skill from each skill set, which could add a little more strategy to the game and allow the player to tailor their character to their playstyle. Finally, the player must choose which skill set is key, aligned, and degenerate, which would further differentiate the character and keep me from being the great stealthy heavy armor-wearing magical warrior that does everything. I should have a skill set that levels quickly, so that I can build a character into something formidable in some way from the start, and as I work, the character becomes noticeably stronger (getting rid of scaling and skills with serious effects will accomplish this).
Any suggestions welcome.