Yeah, I agree with all that - one free switch from one weapon loadout to another each turn seems like a reasonable compromise.
The one thing that you should to be able to do that your suggestion wouldn't allow, is get a sense of your range to a target without having to switch weapons. Currently, you have to switch to your bow and try to aim at someone to know if they're in range. It gets even more complicated if altitude differences are involved, because then it's not just linear distance that you care about.
