Well of course one way to remove the abiguity is to simple increase servers wages to the minimum wage, True this would add cost to the food.
As for tips then it would be the patrons decision as to whether or not to leave a tip instead of feeling under preasure to leave one.
But if servers do better out of the tipping system they wouldn't in general want to change it.
But who would benefit more from the change the consumer or the server/waiter?