Gee - I think that's what this thread was about some time in a past life. How about this one:
If an official stops play due to an injured player, that player must leave and be substituted even if the coach is not beckoned, or that team must use a TO to keep the player in the game. IOW - just eliminate the "coach being beckoned" aspect of the current rule.
I know there would be some issues if this came to pass, but it could be fun to discuss it.
BTW - I really don't care how this would affect table personnel.