In no particular order, here's what I think
(1) Tanks should have a bit more HP. One of the good things about them in the X-com games was that they could take a few hits before dying. Right now they die in 2 hits. I think it should be 3-4 hits instead.
(2) Right now the MG tank is vastly more powerful than the rocket tank. I've never had it fail to kill an alien in one hit, and that's after taking it on several missions. It can also take 3 shots per turn, or more realistically 1-2 after moving, whereas the rocket tank frequently doesn't have enough AP.
(3) You should be able to scroll down by putting your mouse anywhere along the bottom edge of the screen. It's annoying to have to move your mouse into the corners before you can do this.
(4) Moving things around into or out of your inventory is too easy I think. X-com punished you for rummaging around in your backpack during a firefight, but this game lets you swap weapons, ammo, etc, quite easily.
(5) Were pistols intended to have autofire?
(6) I would like my guys to be able to move a few more squares per turn with snap fire reserve on. Otherwise battles slow to a crawl, since you can't really advance at all with snap fire reserve on.
(7) If I turn snapfire reserve on for a unit, it should remain on in subsequent turns, I should not have to turn it back on every turn.
(8) If I give a shoot order while snap fire reserve is on, this should override the reserve. I'm okay with the reserve telling me I can't move any farther, but it's clear that if I'm telling my unit to shoot this turn, this takes precedence over shooting next turn.