Please Reconsider Splitting Main and Off-Tank Roles Based on Job

[Carighan]

A more modern game probably wouldn't even implement a trinity design, let alone designate a 'main tank'.

This is correct, although we can see from Guild Wars 2 that just removing tanks/healers entirely (and by default also removing DPS as a role since it's the only remaining one) does not just solve a problem.

You still end up with designated main tanks and healers. Even in such a setup!

And like you say, we already had MT/OT splits. We already had game-decided (not player-decided!) MT and OT splits. In fact we have it right now one could easily argue. Which leads me to ask an important question:
You call it a "regressive change". But since, right now, on live, we have an MT/OT split, what is the "change"-part of that statement? Just that it re-shuffles who is MT and who is OT?

(edit)
And not to misrepresent my opinion, I don't like the idea of some being "the MTs" and some others being "the OTs", I'm merely saying that from all available evidence both in this game and others, it's an unavoidable reality. It - seemingly - cannot be avoided. All SQEX is doing here is adopting the terms and realities the playerbase has already created in the game anyways. The sole meaningful difference is that like with healers, we'll probably see content designed with the idea that you have 1 regen + 1 shield healer, errr, 1 counter + 1 protector tank in your group. Nobody is stopping you from not doing it and in fact by and large the game doesn't even care (see DF group composition results), but the devs won't balance for 2 regen or 2 shield healers any more. It might be fine, it might be optimal, but it's never considered during balancing.

I really don't see the problem with doing that as the devs. Because again, they're not adding an MT/OT split. It exists. Right now. I dislike the names (heavily), but I also kinda dislike that on the healers, and I get that many don't like lyrical names. Heck we don't even call the red role "damage dealers" any more; we've reduced them to the number you see, DPS. They're not even inventing the terms if we're being honest, they're merely adopting the terms we the playerbase already use ingame. Right now.