Can you think of a reason not to?

Thanks for all the feedback. Maybe a bit more context would help zero in on my point.

My intention is to simplify. The Anthem P5 is 135 lbs so that classifies it as a “BEAST”! It is an awesome sounding piece of equipment but it is 5-channels. I only stream movies and music and two channels would greatly simplify the whole setup. Less wires, fewer speakers, etc. I’m thinking an Anthem P2, a decent preamp, maybe keep the AVM60 or a suitable alternative, and just the one REL R528. I really enjoy the Paradigm Signature S2’s. They sound terrific!

Going back to the amp, the Anthem P2 only weighs in at ~65 lbs making it much easier to manage. I would even consider an almost even trade depending on history and condition.

You might consider the purchase of a 2 channel preamp 1st to use with the 5 channel amp while searching for an amplifier. 

Have you considered using an integrated amplifier as opposed to separates?

Since the amp is the heart of the system and the P2 weighs ~1/2 of the P5, I would have all the power and audio quality I would ever need. I've always preferred separates and quite honestly like the aesthetics of the Anthem product. I guess that makes me a bit of a fan-boy. Also service and parts are readily available and Paradigm actually answers their support telephone.

It sounds as though you’ve answered all of your own questions.

Do you have room for 2 separate systems? My credenza fits my 2 channel tube amp and my tube preamp along with my DAC Oppo player and streamer  In the same credenza I also have my Emotiva XMC-2 AV preamp amp and Bryston 3-channel amp for movies