I went this route with a mutichannel preamp years ago and it performed admirably. There are a few other made by Macintosh, pathos, audio refinement, copland and audio research. Actually when I compared it to various receivers it performed noticeably better. I was enamored of the anthem pre/pro but my budget didn't allow. It definitely was better for music to use my audio refinement pre5.
I had to search back quite a few years but I also found the marantz dp870 DD pre/pro. I think Macintosh and rotel made one too. Very handy to have DD for your cable tv (football) integrated as well to your HT and a simple processor that added nothing except DD functionality. the marantz was the only one with a bypass if you don't have dual mutichannel inputs preamp like the para sound P7.
In a purist HT you only need the oppo and cable. The receivers do integrate better with lifestyle wants (wireless, online media, ripped/downloaded content and multi zone). Not to mention the lifestyle approach is just cleaner cable wise. Since i moved to a new home, the HT room is mixed use now and not a dedicated theatre. . Even I admit to going back to a receiver (NAD). But it is still using an extra 6 RCA's since I use an external amp.
I did take the separates route to the extreme. Having an external bass management and a separate video processor in the old HT.