Why not drop the Avengers and call it good? Admittedly you're down to two fairly fragile troops choices for holding objectives, and your screen gets smaller. But you retain every element of your army that gives me the willies. Sure blade storm will dump 2 or three wounds on terminators (if you roll like I do), or kill 3 to 5 tac marines (and of course do a number on more squishy targets) but you have other elements that are just as effective.