To do what you suggest, the Democrats would have to control BOTH the Senate AND the White House.
And, I'd suggest that if the American people ever allow such a thing to come to pass, they deserve exactly the judges they will get. That is the essence of democracy.
Furthermore, I expect that if the Democrats ever did find themselves in such a felicitous situation, they would NEVER allow Republicans to thwart them with a filibuster. The judicial filibuster would be history before you even noticed it was gone, and with less fanfare than a cafeteria lunch.
All the more reason to get as many Constitutionalist judges on the bench RIGHT NOW, while we DO have the Senate and the White House.
Can you think of a better time to do it?