I played through X-COM/X-COM 2/Phoenix Point a few times each, including a couple of ironfox runs in all. I’ve never played any of these below the 2nd hardest difficulty. I’ll usually reload missions if I screw up badly enough, but won’t use saves to the extent that I’m just rerolling individual shots. I’ve really enjoyed all of them, but I think X-COMs ruleset overall was simplified/abstracted too far in the direction of boardgame style play e.g. 2AP with most actions ending the unit’s turn immediately, and some very weird looking line-of-sight issues when firing (specifically from overwatch).
I really love Phoenix’s 4AP system, it’s a neat compromise between the ultra-streamlined 2AP system and the numberwang soup of the OG games. I especially like that you don’t consume an AP all in one go when moving (so you can move, shoot, move and usually have a full AP left over). Plus the manual aim/every bullet is modelled system is so good.
On the other hand I think it has a lot of problems after the mid-game. Things drag a bit and I end up resenting getting dragged into missions that are way below the abilities of my team; an autoresolve would’ve been great in some contexts and would certainly help ‘haven defence burnout’. I don’t recall this feeling being that prevalent in either X-COM (maybe WOTC?).
Balance also skews in weird ways that aren’t entirely satisfying. Losing a soldier from full health due to a single sniper shot always feels cheap and becomes an issue from the midgame onwards. Unfortunately choices to mitigate against that are kinda limited since armour plateaus at a midgame tier despite weapons advancing slightly beyond. You may lose a soldier in a single turn in X-COM but generally not due to a single shot. Lots of other examples but I don’t want to get into the weeds. I think my simplest take is probably that X-COM’s streamlined approach serves it better over the course of the entire campaign whereas Phoenix really gets off to a great start but gets too… muddled by the end of it (actually, this is something I feel is true for WOTC also).
Perhaps my biggest complaint is that tonally I think Phoenix Point squanders its premise and never lives up to the horror aesthetic it threatens; it’s a very generic looking apocalypse and the weirdest/creepiest thing you’ll see are, oddly, havens belonging to the Disciples. X-COM did a better job with its setting (more of a ‘thing’ in 2, admittedly) but on reflection it pivoted so hard into a Saturday morning cartoon aesthetic in WOTC my feelings there are mixed also.