I waited tables for years. (I was good at it, and even helped train everyone at a new restaurant.) Hourly pay would have definitely lowered my wage, but it's still better than tipping. It'd be cool to get hourly wage, or even commission, so that your pay isn't based on people's whims.

servers who were bad at their jobs would get paid just as well as servers that offer good service.

(Note: I use the general "you" a lot. You're just repeating what someone else said, I assume you don't have any wait staff working for you personally.) You can fire people for being bad at their jobs. Why do you have bad staff working for you, tips or no? How about: Unattractive people will get paid just as well as traditionally attractive people. Minorities will get paid just as well as whites. Your salary doesn't hinge on whether you can sneak extra stuff to your tables without your boss finding out or putting up with sexual harassment. Salary means that my paycheck comes from the restaurant and I don't have to try to balance the interests of the people paying me against the restaurant.