I really like Scourge of Fleets as a card that has application both as a stop gap against midrange strategies in grindy games as control/as a sb card for those mirrors in midrange (assuming your cube is sufficiently slow), a finisher for big blue and a generally good ramp target to clear the board and allow for alpha strike. Not needing to have the board under your control for Scourge to work is very nice, and while the draw off Sphinx is nice I think generally control already has enough draw effects without needing it on your finisher.