I didn't play the update yet, but the reading is god. Thanks for taking care of your game.
I personally don't care about controller support.
Further addition to the game would be more variety: tilesets, map shapes, enemies, weapons, equipment, starting situation (team split, hit and run, sabotage with real consequence on the next mission...), classes or maybe new perk per class to make them more unique even.
Also, more options, instead of Classical/Casual, check boxes. Permadeath yes/no, health+/-, retry mission yes/no... and let the player pick whatever it wants, without forced penalty/bonus. Like, i want it all hard, but without perma death. My choice, it's a single player game. Or i want perma death, but with one chance to retry a failed mission once per main objective. Or any other combo.
Also maybe, some starters for fun : cannot have more than 3 characters in mission. Cannot buy mercs. Class XYZ disabled. Start mission with 1 hitpoint...