It would be an interesting test of what is actually "must pass", though.
I also think it would encourage less partisan and more consensus-built legislation if the number of votes it passes with extends the amount of time before it sunsets, esp. if the relationship is not linear. Right now, if you have 50%+1 vote in the House, and 60 in the Senate, you don't have to care about the rest, so you can make legislation as extreme as you can while remaining within those boundaries. But if the difference in getting extra votes is a renewal vote in 25 years (with, say, 3/4 supermajority passing) versus just 5 years (50%+1), those extra votes may well be worth fighting for with some concessions.
I also think it would encourage less partisan and more consensus-built legislation if the number of votes it passes with extends the amount of time before it sunsets, esp. if the relationship is not linear. Right now, if you have 50%+1 vote in the House, and 60 in the Senate, you don't have to care about the rest, so you can make legislation as extreme as you can while remaining within those boundaries. But if the difference in getting extra votes is a renewal vote in 25 years (with, say, 3/4 supermajority passing) versus just 5 years (50%+1), those extra votes may well be worth fighting for with some concessions.