I'm very sure he'd wipe the floor with Elizabeth Warren as well, but at least she might not totally embarrass herself. The first three? I think any of them might start crying on stage, or physically attack him from sheer rage.
THAT would be pretty awesome. Cruz wouldn't fall for, or present, a personal attack, Trump would lay into Obama and Hillary with his usual flair, and Cruz would make his exceptional arguments.
Let the RNC block Trump from the debates. Let Trump make his own debate, invite Cruz only, and have Camille Paglia moderate. Ratings would top the 10-man folly on Fox, and the other 15 candidates can flounder together with 1/20 the ratings.