I am here just for Overwatch, so I’ll just answer to what I care about (I couldn’t care less about hair color or animations, visuals are last on my expectations list 
of a TBS game).
I think of it as an integration bug (two systems work as intended, but integration between them works in an unexpected way). Overwatch is triggered by non-idle animation, but ther is no door opening animation so it doesn’t trigger at all. I woudn’t mind if enemy was sideway (left or right of doorframe), it would make sense, but enemy appear “out of nowhere” in the middle of a doorframe covered by three OW cones and is ignored by everyone (“must have been the wind” :P). If that is really intended, I don’t want to play this game at all.
I don’t find this (at least that part I have on my mind :P) a bug, but a very bad game design (I guess because that is how “cinematic” camera works in this game). Overwatch is triggered sequential instead of simultanous. If I OW same spot by multiple soldiers (create “killzone”) I would expect them to immidietly shot at anything unfortunate enough to move there. Yet… they don’t. The slow-mo animation starts, and my soldiers take turns (because that part is turn-base apparently), lean in slow-mo out, takes a shot, leans back. And then next soldier in slow-mo leans out, takes a shot, leans back. And next soldier. Turn by turn. No big deal, one could say it is just visuals and he could be right… if not the fact that for the whole time my soldiers take turns, enemy in slow-mo runs wherever he wants, often behind cover long before even second soldier has opporunity to do his action. 
So rest of my dumb, sad soldiers shot a wall, a box, a pillar, even a friend in a back because enemy position is still ray-traced regardless of him being long gone and unhittable.
So, for three OW soldiers see enemy:
- expectation: all of them shots enemy at the same time (or enemy is frozen in a position, not slow-mo doing whatever he likes :P),
- reality: “wait for it… wait for it… wait for it… aaaand he’s gone behind the wall, oh no, silly me”
Similar as above, if that is intentional, I don’t want to play this game at all. 
Ref. link: Are you guys ever going to fix overwatch?