Do I still need a receiver?

[ls7z06]

I have been running an Onkyo TX-NR5007 receiver using it as a preamp for my fronts, center and surrounds which are powered with separate amplifiers, ..... while using the 5007 internal amp for my back surrounds. My primary source is an Oppo BDP83SE. Secondary sources are HD cable box, PS3 and iPod. I listen to a lot of multichannel SACD and a lot of 2 channel stereo. So.... I have now ordered a Parasound Halo P7 multichannel preamp trying to get the best musicality I can from my system. It should be here next week.

here is what I was thinking....
I will also buy a Parasound Zhd HDMI switcher that works in conjunction with the preamp. That would keep me from having to double switch audio and video. I am also planning to drop my rear surrounds from the system and go back to a more traditionalist 5.1 surround for a host of reasons I won't get into in this post. So...I don't see that the receiver is really doing anything for me now. The Oppo decodes all of the latest formats, allows for bass management and speaker balancing and upconverts DVD to 1080P. By running other sources through the Zhd, I would be putting my HD cable directly into my TV at 1080i and my PS3 in at 1080P with no additional pre-processing. I think the only thing I am giving up is the upconvert from 1080i to 1080p from my cable box....and that's not a big deal to me at all.

Is there any other reason I still need the receiver? I think this would be a simple, clean, lower temperature, lower energy, and better sounding arrangement. Comments appreciated.