I'm usually with you and your rational arguments, Flash, but I think much different here. Term limits are no more artificial than direct election itself. In fact, it would be hard to say what is "natural" in the sense that the founders of the nation used it when building a system of elected government. That's probably why they argued so much more about it than anything else. Why is it that the general approval rating for the legislative branch is yearly very, very dismal, but people still vote for their incumbent when elections come around rather than installing new blood? Answer that. Well?
I have an idea. Could it be that our populace as a whole feels (or is) completely ineffective politically? Voters just can't believe or don't realize that their elected official is a part of the political class that is currently doing so poorly at running the country. Until the turn of the century the Congress voted on who would be in the Senate. This measure was in place to keep the Senate from having to tap dance for the electorate. Now all they do is tap dance and pull out the occasional flaming baton. They do this because it works for them and they're good at it.
Stop the tap dancing. Imposing term limits would get the Senate back to the real business they were meant for. The system of government we have is really great, but it's not functioning the way it's supposed to right now. Granted, it is intentionally set up to make it really hard to get anything done (less than 30 amendments anyone), but the move that Senator Specter made is an indicator that the government has jumped the tracks. It shows that he truly is a member of the political class. This is a class that should not exist, or at least not in its current form. The idea of For the People and By the People makes no room for a political class like the one we have, yet we still have it. This is the problem that term limits solves.