We'll have to agree to disagree. Homogeneity in function is not a problem as long as variety in form is achieved. Thats the only way you get "bring the player, not the job" as a reality.

Are SE successful in variety in form? Not always, but no caster plays like another. They don't focus on the same tools for movement, they don't approach group burst the same, and aside from knowing how to slidecast and its uses, they are very different.

This has been true since StB. Summoner's current predicament aside, its a strong record as far as casters are concerned.