Balance, Homogenisation and Encounter Design: The Problem.

[linay]

Will we ever reach the desired “perfect and purely balanced” world, where in return it doesn’t matter at all which job you choose to play?

That's up to the players. From the game's perspective, it already doesn't matter now except in certain situations, like needing caster LB in a fight. As long as people feels the need to dictate what others play instead of accepting the diversity in choice that people have, what job you play will always be an issue. Balance is only needed as far as making sure all jobs are viable and nothing more.