You re bound to have homogeneization when the hardest encounters are designed to be played with merely 8 players and there are far more classes per group spot in any given role.

For the content to be completed with any class, then the jobs/encounters must be homogeneized.

That s why MMORPGs have been at a stalemate since blizzard invented the "bring the player not the class" of wow 3.0. It basically killed the depth of group play in MMORPGs.

TL;DR: Homogenisation may seem the answer to balance problems, but instead it’s the indicator of a much bigger problem: the lack of variety and nuances in encounter and activity design.
You are like 10 years too late for this debate because since then it is the standard of MMORPGs.