Might do. Depends how "compatible" the sounds of the two amps are. Do they have the same gain which may affect biwiring? The Rotel may add some colour to the sound which you don't like or it could be just the change you are looking for. You certainly won't be lacking in any power tho'
Sometimes I guess you might be lucky, but a lot of the time it may be a case of how nit picky you are. I know i havent managed to biamp using 2 different amps, but this maybe because I listen to my front pain a lot for music uses. I cant qualify whether biamping with unmatched amps will be particularly bad for performance in a cinema only set up. I would still think that the amps need to be pretty closely matched else, even with cinema, the sound wont be particularly nice.