Why having a dedicated MT and dedicated OT is a TERRIBLE idea

[Kaedan]

I didn't read the whole thread, but most I've seen now are discussions on abilities, enmity and so on. So I'll just leave it at that.

When thinking about how 2/4 tanks will be better at being MT and the other two being better at OT, this comes to mind first:
Personally, from the 3 tanks we have now, I like Dark Knight the most. So when I play tank, I most likely go as DRK. My boyfriend prefers Warrior.
What I'm saying is that there are a lot of people that don't like all tank jobs equally, but prefer one of them.
The biggest problem is that you are actually forced into playing MT (or OT resp.) all the time. So if someone prefers to play PLD he will actually never MT, even if he would like both or even prefer to MT (not counting groups where people don't care because usually even casuals care after they read about meta and so on).
It's already like that now, so I was really kind of hoping that with the next expansion all tanks will be equal - or at least almost equal - at being MT or OT.
I don't mind either in normal content actually. But when learning something that's harder, I actually prefer being OT because as rarely as I tank, I'm not the best at boss positioning. For example: If DRK/WAR will be dedicated MT I either have to MT even if I don't like it, play PLD/Gunbreaker (what's the abbreviation? GNB?) or not play tank at all.
(Yes, I know there are tank swaps. A lot of fights only have them for short periods of time though and it's not even between the tanks. Or if there is no debuff the MT provokes back/gets covered etc.)

But that's not actually going to be the case.

There will be plenty of situations where two OT or two MT get put in an instance. One of the OT can still do the MT job fine, just like one of the MT can still do the OT job fine. The concept they are going with where there are 2 tanks "suited" for OT and 2 for MT does not exclude them from being able to do the other role. Right now we have instances all the time of two PLDs in the same party, and one can still easily MT no problem.