Class Homogenization.... Why do you want it?

[Meklore]

remember lolDRG anyone?

With too much specialization there will be exclusion to certain content by players who only want to use the optimum setup for the fastest exp.
That was a lesson learned from XI.

[Tarta]

So I enter an instance, I am DPS. I do what I can. Fail in the fight. Get told Class B does much better for this fight.
I then switch to Class B, do the fight better. Job done.

I enter an instance, I am tank. I tank the mobs. I have a hard time. Get told Class B does it easier for this fight.
I then switch to Class B, do the fight easier. Job done.

I enter an instance, I am a healer. Hard to quick heal things, long cast times. Get told Class B does it easier on this fight.
I then switch to Class B, do the fight easier. Job done.

I don't understand the reluctance of people to understand the concept.
If you want to stay 1 class, good: just be ready to have a harder time on some encounters and an easier time on others.
The barrage of whining...it's aggregating blood clots in my Frontal Lobe..nggg...nuuhhh, gwaaaa

(This is of course, speculating upon your next queue).