The biggest issue is that there are no term limits for members of congress (and I'll throw in supreme court justices as well). How is that we can limit the term of one out of three branches of government, but not the other two? I thought checks and balances were part of the governmental setup, so surely what's good for the goose would also be good for the gander, right?
This goes to state level as well. We do not need life long politicians, who will invariably be more concerned with getting re-elected instead of passing (or blocking) meaningful changes.
Lets say we use the same conditions that President has to operate under, a maximum of two terms of four years. You could still make most of a career by starting at a state level and working to federal. Eight years as a state rep, eight as a state senator, eight as a federal rep and finally eight as a federal senator. Thirty two years in politics is plenty enough to retire as a normal citizen.