Being able to use the tab button to cycle through units is nice, and being able to use num pad to cycle is sweet too. I would also like to have the ability to mark my units turn as being done. Then when I hit tab the unit doesn't get selected. The number at the top, representing the unit, could also be changed to a different color. A new button next to the stand up\squat toggle button to set as turn is finished would be nice. And a hotkey would be nice too. This would help with managing the units turn better.
This is not a unique idea, and was implemented in the original, tftd, or playstation version of ufo defense, if not all of them. Forget which it was, sorry. And it seemed to work well.