I'd also make an argument for some form of term limits for each branch of Congress: perhaps no more than six terms for a Congressperson and three terms for a Senator. The argument of the geriotcracy is a one that, frankly, we should have confronted by the end of the 20th century at least. That Strom Thurmond and Robert Byrd stayed in the Senate until they were in their nineties was ludicrous beyond belief and there are so many example I can think of in my lifetime well before Dianne Feinstein became the most obvious example.
There's also an argument, I think, that there should be more strict requirements to become a legislator in the first place: the Constitution only gives an age requirement and a citizenship one. I think all potential legislators should at the very least be required to take and pass the kind of tests they have to become a citizen. And maybe as a dig at the GOP we could have those member take the kind of literacy tests that made Jim Crow impossible for African-Americans to vote ifor nearly a century. As I recall that was the kind of test nine out of ten college graduates couldn't pass. Well, if it was good enough to restrict the rights of minorities = which as we all know they want to do - they should prove to the rest how easy it really is.