I'm partial to QuakeWorld myself. That movement is so gooooood. Brood War was amazing, but there are definitely some nice quality of life changes it could get, like larger selection groups. I'm fond of Beyond All Reason and Zero-K these days for RTS.
Discussion
No, larger unit selection groups would favor zerg too much. With remastered they barely touched the game itself which is good. They made the engine handle more stuff and fixed some minor things.