Term limits are desirable because it minimizes corruption and arrogance, not to promote diversity.
Anyone who believes diversity was the goal must be brain-dead.
From what I've seen it increases corruption because politicians nearing the end of the limit have to start considering what their next step is.
Taft, here in Ohio, has been known to award political appointments to legislators after they are forced out of office by term limits, if those legislators switched their stance on some issues Taft considered important.
Politicians who are planning on moving up to a higher office often start using their office to appeal to a wider group rather than looking after the interests of those they represent.
Instead of minimizing corruption the minimize their accountability to their constituents in their second term.
Arrogance is usually mitigated by accountability. I don't see how removing a politician's ability to be reelected encourages them to be LESS arrogant.