14 channels? I'm presuming that you are doing a multi-zone setup?

I think that for most people, the point of a higher power amp isn't loudness per se, unless they have innefficient speakers. For instance, my Kenwood 6 channel 100 watt amp plus the 990 is painfully loud at reference level when playing something like the Matrix.

I think that what the extra power is supposed to give you is an overall cleaner sound at higher db as the amp doesn't have to work as hard to push all those extra electrons, but correct me if I'm wrong in my thinking or if the extra power gives additional benefits beyond that.

Of course, whether the 7700 does this versus the 7125, only those with direct experience of the two can answer that.