I would really dread the thought of a Senate without Yankee, the man is the Senate!
I used to hold that opinion for no particular reason, but it's become clear that others are more than capable of doing Yankee's old grunt work, particularly after the rules revision, so I'm not sure what this means.
Yes, other Senators can run the Senate without major problems, Bore, TNF and I did so over the past few months. My point is that Yankee has been in the Senate longer than anybody (over half the Senate's history, I believe), and he has some unique experience that along with his strong sense of duty make him a symbol of stability, continuance and so on. (Not to mention that he has been the unofficial Senate leader for the center right for a very long time)
Should he leave at some point, his absence will be very strongly noted.