1. Wage: The costs would be passed along, but they wouldn't be an option based on quality of service. Also the 'server as a profession' would probably be killed, as high scale establishments would pay less than tips account for, and taxes would be a greater portion of that.
2. Taxes: Restaurants have slim margins, and to keep them viable the customer would be paying this difference to the government. It might be 'just and right' but I'd prefer not.
3. Tipping as a percentage of the total bill: That's optional, unless you have a large group. It's just an easy way to calculate a reasonable tip. No one is going to fault you for devising an alternate calculation.