This is sort of an alternative answer to one of the issues that Brian highlights in his post Skill Atrophy. The part that really struck a chord with me was the comment about higher level characters becoming more generic as they learn a broader range of skills once they have maxed out their core skills.
I really hate ‘generic’.
Having said that the character design criteria I ask my players to aim for is a well rounded character who could have survived to reach level one. I like characters that have some kind of answer to the problems of healing, being cornered in a fight or lost in a hostile environment. I don’t want everyone to be the same but also don’t like characters that are pretty one dimensional.