I'd like to be able to back out of a called shot without closing the attack window. Not really a bug, just a convenience, similar to Iceman and BBlue requesting being able to hit 'x' with the window open.
Also, if something happens which makes a called shot possible that wasn't before (e.g. the enemy fails a pilot check and hits the ground, jumping hit %'s above 85), it'd be nice if the called shot crosshair appeared immediately. Currently, you have to back out of the attack window to get the crosshair. Once again, not a bug, just a refinement.
On the attack menu, a shortcut key for "Wait On... Unit... New Enemy" would be helpful (i.e. instead of hitting three keys, hit one). This may have been mentioned already, but I can't remember, and I use that sequence frequently.
Another idea for expansion/sequel, I think it would be cool to have fixed implacements. Not really as an option for players, but for the editor. I'd like a scenario where the player's Titans have to assault a fortress with gun and missile turrets surrounding it. Buildings already have HPs, just let them shoot back

. Maybe a stretch, I know, but it's an idea.
widowmaker
"The trick is to be angled just right so when your Titan's engine shuts down, you fall behind the cover."
--"Running the Redline", page 37.