We have term limits. They are called elections.
Term limits would result in nothing more than hired (I refuse to use the word "professional") operatives running the government and having the organizational memory, rather than elected officials.
And, even if the radical contingent were thrown out (the likes of Schumer, Rangel, Jackson-Lee, Waters, Pelosi, and their ilk), they would be replaced by others no less wacky.
America has to change from within to elect reasonable people to Congress and the Presidency. Term limits aren't the answer - we need to work at the grass roots level.