1 seems like common sense. Having physicians (effectively) randomly waste their ability if they target the same person is bad for the game, strategically. If people think there should only be one DK revived per game ever, they should suggest that, but it shouldn’t randomly happen when two physicians coincidentally target the same person, and otherwise allow them to use their abilities in sequence.
Basically, wasting a revive is too “swingy” - it has dramatic impact on the game based mostly on luck. The game should try and minimize that sort of swing unless there’s useful strategy attached to it (and I don’t see it here.)
The other two suggestions seem unnecessary, though. Wasting your revive forever because you both chose the same person seems unacceptably bad design to me because of the massive swings it can cause based on little more than luck, but wasting one night is fine and not nearly such a big deal.
And DKs can already know who revived them… if the Phys indicates it the next morning in public chat. That’s a trade-off, of course, but it’s a strategically interesting one, so I don’t feel they should get that knowledge for free.