Those are very nice amps. Any changes would probably end up being downgrades. If you want to reduce the number of amps, just get rid of rear speakers, or if you must have rears, maybe bridge one of the 2-channels to power front/rear and ajust volume level on rears using L-pads.
If you do want to go with another brand/model, I would still get 2 amps, one for speakers and one for subs. Not that many 5-channel amps that have a decent bass output in relation to the other speakers.