The Star Wars game has an elegant solution to this.
Each class gets class skills and non-class skills.
Both sets of skills go up by 1/2 rank per level automatically.
Class skills get an extra +5 to the skill.
And, a PC can take a Skill Focus Feat that gives +5. So, this allows any PC a little extra capability in some specific desired skill.
For example, at level 10 with +2 stats, it works out to:
+7: Non-class skills
+12: Class skills (or non-class skill with Skill Focus)
+17: Class skills with Skill Focus
In current DND, the max is (still assuming a +2 stat):
+8: Non-class skills (but usually much lower)
+15: Class skills
+18: Class skills with Skill Focus
Balance-wise, this seems reasonable.
The designers also combined things like Search, Spot, and Listen into a single Perception skill. The great thing about this is that it takes a LOT less time to create a higher level NPC for the DM.
It is also trivially easy for a player to take his PC from level x to level x+1. If it is an odd level, none of the skills improve. If it is an even level, they all improve by 1.
If there is any set of rules in 4E that WotC should adopt, this DEFINITELY is one of them.