Being able to select more than one group at once would be nice.
Also, I have found that when moving a group from one place to another, they would stop moving to their destination when I tried to move a different group at the same time.
This was particularly problematic when playing the "Save the archers" mission. I was trying to move the archers away from the enemy, while at the same time, advance the other two groups to attack.
I also found it a bit hard to move around the map with the mouse, and trying to find other enemies and allies was pretty difficult. I think you should increase the range on the corner-indicators to an infinite length, so you can see where everyone is - or add some sort of mini-map.
That aside, I loved the graphics.