In order to homogenize the dps classes they would have to either make it so that the combination of the damage you deal directly and the damage you add to others would be equal to all classes with their different and unique buffs/debuffs, OR they should remove all utility and then equalize the direct damage classes deal.

The 1st one is what SE tries to achiev, but it is pretty hard to do since the uniqueness of utilities makes it so that comps will play a hug factor on how much damage you are adding, and the second one would bring the wow problem where raids stack classes that are stronger in order to have an easier time, and since it is much easier to level and equip an alt class in ffxiv than it is in wow so you could expect this to happen even in pugs.

Now, there is another factor that is the difficulty to perform with a job. If SE manages to perfectly homogenize all jobs so everyone deals the same virtual damage(direct damage + damage add to the group), then the easier/less punishing classes would end up as the stronger class. Let's say for example that RDM and BLM are dealing the same virtual damage, in this case RDM would be the stronger job, because it is far less punished by mechanics that force you to move, stun/silence you and things of the sort.

Should they make it so that classes overperform others depending on the situation? This brings another problem: What happens if a raid tier has many encounters that favor one job? Talking again about the RDM x BLM, what if a raid tier has 4 fights that don't require much movement? BLM would come on top, and RDM would be just left in the shadow. But should raid design be limited so that an even number of encounters favor different classes?...

And this goes on and on and on, every answer brings on more issues. I think that they should be going down the line of thought that I described until they find the spot with 'more acceptable issues' and then stop there, perfect balance will never come.