It doesn't matter. "From each according to his ability" doesn't work. People won't put up with it.The wealthy are the ones who are getting the most out of the system, so then why should they not be paying the most into the system?
Think of it this way - what if, instead of playing games with the tax code, we just limited their income in some other way (salary caps or whatever)? Let's say we decided doctors were making too much money and capped their income. Do you think that would affect the number and quality of people pursuing a career in medicine? Of course it would - we can argue over how much, but it would definitely negatively impact the supply of doctors.
So, more generally, if we target people according to their ability, it will have a negative impact. Many of the people with ability to spare will refuse to cooperate. They'll move, cheat, hide their economic activities - or just drop out and refuse to contribute. Not all of them, certainly, but enough to have a serious impact on our economy and quality of life.