Clearly you guys are further in than I am. I have school, so I've only had 3 sessions with the game (though two of them were marathons).
I do feel you on that grenade point, Sy. There were a couple times I did accidentally fire a rocket or toss a grenade when I didn't mean to because I forgot it automatically pulled them out. And there's been a couple times I got jump with the controls and accidentally hit X or ^ when I shouldn't have and lost a turn for one of my dudes. Never had an issue with sending guys out too early, though, and I always save before I go into any potential battle anyway.
Things seem to vary by individual more than class, I'm discovering. I haven't really looked into why. Like do some guys have better aim? Because my heavies can't hit the broad side of a space-barn. I'll march them straight up to guys and they'll get like a 78% and then usually whiff completely. I fucking hate them. I'm tempted to get them killed I hate them so much, especially since their dumbfuckery has caused missions to go south at a number of crucial moments. The only thing they're any good for is suppression.
My snipers sucked ass in the beginning, too. Though oddly enough, they seemed to get lucky a lot. Sub-50% hit rates but they'd often roll in the right range and get a hit or kill. But they've really beefed up, and I'm not sure why. I had scopes on two of them all along, and it's only after upgrading to the laser sniper rifle and getting them to major that they seem to now consistently be getting really high hit rates, and they can kick the shit out of key enemies at the beginning of a good turn. But I don't understand what caused the rate to go up. Does aim improve with rank? Because Deacon, one of my supports, is a major and he still can't hit a fucking thing. He's pure medic because he sucks at everything else, and unfortunately he doesn't even move all that far.
Support and assault are my bread and butter. My first colonel was a beefy assault, Angus somebody... got the nickname Duke, so that's all I know him by now. He started kicking ass with a shotgun early on and rapidly rose through the ranks, and he's my go-to guy for basically everything. Laser shotty now, and he's got the thing that gets him free reaction shots for guys entering within 4 tiles and he gets increased critical chances for close enemies, so he's always on the front lines with the best armor soaking up fire and taking on melee. He's killed berserkers basically for free. Like take a shot or overwatch shot, they use their ability to rush him, he takes a free shot, they rush him again, he takes another free shot, and they're dead. I love it. He crits a lot. His second in command who I think just got to colonel herself is Holly Williams, who I love because she got the nickname "Smokes". Holly Smokes, I mean how fucking great is that? She's support, and she's had the highest hit rate of anyone in the organization. She's easily my fastest unit (again, do they have stats for this shit? Why do some people move so much further than others? It doesn't seem to be based on class... I think she took the thing that lets her move 3 tiles more, but it still seems like she outruns people by way more than that), and is super versatile due to her ability to both kill shit quickly (especially right now... she's the only soldier I have that's carrying a plasma rifle) and save all the other poor sods who end up getting themselves shot up or knocked out. The other one who's up there with those two is a female assault, part of a group of 3 high-ranking officers I have from Australia (I also have a two-man Irish team that goes out together a lot, a sniper and an assault), and one American assault and American heavy that are up there.
Haven't gotten any psi stuff yet. Just getting into that now.