i might rather suggest reducing the number of judges on the court. they're expensive, dammit. you don't often get more than three unique positions, up in canada; there are a few judges that i can't be sure have ever written an opinion of their own at all.
five is probably enough.
sanders' idea of cycling the judges up and down would probably create an anarchy in precedence. you don't want cases thrown back and forth between judges, like you throw bills back and forth between houses. as much as i dislike government, i'm an advocate of the court system; it's probably the only hierarchical system i'd leave in place.
but, what he's trying to prevent is cutting a career short due to term limits, while still allowing for renewal. it's a kind of compromise that prevents stagnation without sending people home early.
i don't like term limits either, and for the same reason (amongst others), but i think there should be a mandatory retirement. in canada, mandatory retirement from the supreme court kicks in at 75 - then it's time to go home.
bernie has been remarkably consistent in his views for a long time. but, one wonders if his views on this particular topic have evolved or not; it's easy to see why he doesn't pick the right option today, which is somewhat glaring in context - he almost always does.