I'm playing this again now that I got EW and I think I've figure out exactly what it is I dislike so much about the tactical combat in this game.
You can't flank the enemies, but the enemies can (and will) flank you. Oh sure, flanking is a thing you theoretically are capable of, but it's almost never a good idea because of two reasons:
1. Losing a soldier is much, much worse than the enemy losing an alien. Even if you killed 5 enemies for 1 soldier lost, it would still be a bad choice most of the time. if you flank the enemy, you MUST kill every single activated enemy that turn, or they will counter-flank you and you *will* die. Overwatch is too weak (why is there a massive aim penalty?) to protect your flanker, and combat is too RNG to be sure of killing all the enemies.
2. There's too many monster closets for the tiny map sizes. If you try and flank or rush the enemy, it's almost 100% certain you will open another monster closet in the process, and they will instantly get a free move into firing positions, ready to facerape you next round.
You are heavily punished for poor positioning (as it should be), but on the other hand you're not rewarded for clever positioning and manuvering, and can't punish the enemy for his poor positioning.
That means there very little actual tactics and it mostly just comes down to sitting in cover and making lots and lots of 45% - 55% shots, which is very RNG and unsatisfying - especially when you miss all 4 of your shots, then the enemy crits and instakills one of your guys (or something similar).
Of course then midgame rolls around and you become overpowered and the game loses most of it's challenge but that's a different issue.