From my standpoint, I want to see the developers talk us through how they've thought this out, to demonstrate that the potential problems have been evaluated carefully.

At the moment, the terms MT and OT are just a convention used by guide-makers relating to who takes enmity first in the fight script. It's a bit like saying that you prefer the melee M1 position because you like the west corner more than the east corner. There are differences in how the mechanics play out, but you should be able to do either if you're flexible.

This is a bit different. Your MT will want to have enmity for as long as possible to maximize their damage output. If there's a forced swap, your MT needs to swap back as soon as possible to get counterattack procs. If the MT is not the active tank, then they will likely be expected to stand in avoidable AoEs to proc their counterattack to avoid 'griefing' their party with lower damage. There will probably be entirely new 'MT uptime' variations to every strat with different swaps once people get their initial clears and want to maximize damage (and you know how well NA/EU PF handles variations in strategy). You will see lots of PF arguments over who gets to tank and for what parts and over how it impacts their personal damage. I don't even need to see that conflict arise to feel disappointed in it.

And that's in the best case scenario, where MT counterattacks translate into a meaningful damage difference. If they don't, then a lot of groups will deliberately run double OT for the convenience around not having to cater to a MT, and better raidwide mitigation.

I do think that they need to change things up, but there's no point repeating a design decision that we know doesn't work out from past history. Counterattacks are a great idea, but they should be tied to intercepting specific attacks (i.e. an Interject style move) rather than recieving damage. If you did that, you could even make some tanks proc their counterattacks off of tankbusters, and others off of raidwides. I recognize that they've committed to splitting the tanks, but having an obligate MT that has to take damage is not a good idea. You don't need to 'wait and see' if you played Heavensward and Stormblood. Show me how this time is going to be different.

If they were really committed to mixing things up for tanks, we'd see an overhaul of the entire defensive toolkit, which has seen a progressive power creep over many expansions.