If you're aware that someone is down and bleeding out after combat, then can't you just go into force turn-based mode to stop the other members running around to regroup?
You would have to be fast on the trigger, but it would accomplish the same thing as staying in turn-based mode if a party member is down.
You could have to do this manually, sure. Or the game could just do this automatically, something that would benefit ~everyone and harm ~no one.
Plus, I'm not sure if this applies to resuming turn based mode after combat ends, but after manually ending turn based mode you have to wait 6 seconds to re-enter it. Time in which your downed companion might die.