I'll throw in my 2 cents
1) Reactive targets would be a big plus. Standing still in a lane blasting away at paper gets old after a while. One of the reasons I usually shoot outside is because I can use steel targets and practice moving around.
2) Allow people to practice drawing from their holster.
3) No silly rules about having to buy your ammo at the range. For rental guns I make an exception; your guns, your ammo.