Put a button on the room assignment list, next to each name, to select that dweller. This would make it a lot easier to select them, and also allow players to monitor health bars. Like when dwellers are standing on top of each other, or when health bars disappear entirely (usually when fighting molerats. Drives me crazy)

Also, unless there's a good reason the list is so small, make it big enough to show all six room slots at once. Or a button to expand it, instead of needing to scroll.