The term limits that apply to the President of the United States have served its purpose to prevent a monarchy.
However our founding fathers did not foresee a couple of problems.
1. The people do not seem to have ability to cross party lines to replace members of Congress. So for the House there is an over 95% chance to the incumbent will be re-elected, for a Senator it is 70 -80%. Not much change going on here!
2. If Statesmen were running Congress their actions would be for the "Good of the People" and not themselves. To be fair I am sure not everyone is in it for their own bottom line, but I am also sure that many are.
To ensure that new ideas and methods are introduced to Congress on a regular basis I recommend a Constitutional amendment to establish term limits to Congress.