@Lyinwitchinthewardrobe
Your post there has me all sorts of conflicted 
Why would tipping make any difference to that, swanlife? If a customer sits for three hours then you can't seat anybody else - regardless. Slow eaters - ditto. Whether they tip or not?
What's it to do with you, exactly?
Well, the front line waiting staff are the ones that get the hassle when there's no table, or when a table was vacated 3.6 seconds before and someone is complaining it's not been cleared and they want to sit there because you haven't had time to walk to the table from the other side of the restaurant and don't apparate...... And then the customers who ignore the wait to be seated sign, jump on the only free table and raise merry hell when you point out the bloody obvious reserved sign and there's no where else to sit..... So it does have a lot to do with the waiting staff because we deal with that, and often it'll get personal too.
That said, I think you're absolutely right that tipping does not excuse behaving like a twat. As I've said in previous posts, I'd rather someone was polite and reasonable but left no tip than downright rude and left a large tip - feels like they're paying to treat me like shit which doesn't sit right at all.
they charge more to customers directly and openly, then I'd be happier about that - they'd make waiting staff's lives better so win/win.
Only it won't go to the waiting staff in the majority of cases, I agree with doing it openly and honestly but I don't think it'd work like that to be honest, I think it'd get swallowed by the establishment.
You're also right I think about not expecting tips or relying on them - I don't, they are massively appreciated when they are given, but I budget with my wage not wage and tips.
I don't think anyone should feel pressed into giving a tip, regardless of the level of service given.