1. That's the TM problem (which everyone knows is too OP even for psi), not the combat system problem.
2. No, unless you play exclusively glass cannons. Most builds will be able to survive Carnifex turn if they prepare properly.
3. So now you gonna watch enemies taking turns after every action you do. Don't see how it's any better. Game already had 500% actions speed, there never was any need for "time hack apps" for combat.
4. It's not more "immersion breaking" than anything else in turn based. Or rtwp based for that matter.
Do you really think the same devs who made Underrail and Expedition will release something unfun, or that lacks strategic depth?
Yes. If you want blind faith, go preorder some AAA crap. Or join a cult.
Abilities like Bullet Time can also be really OP in combination with a long player turn, so it's really not just TM.
And enemies will definitely not be taking turns, they will all move at once, which would be a massive improvement in speed. It would also lead to some funny moments where say 20 Expedition locusts all spit at once and instagib you, but that just comes with the territory.