In light of all the problems having the ammo pack on the ACE tool has brought, I suggest putting it on the F key, along with the abilities of all the other classes. All engineers have it, and should use it, often. This may have been suggested before, and if that is the case, I apologize. The problems with the current solution: -People don't know they have ammo on the ACE tool. The F ability is more obvious. -The switching back to primary weapon issue would be solved as a direct consequence of this.
This would become an issue once we get more ACE abilities. That said, I wouldn't mind a way to hotkey specific ACE abilities.