Something definitely seems wrong with your setup, if you cannot hear dialog from the Denon. Have you done an Audyssey calibration? That would help detect some wiring issues as well. I discovered after moving some equipment around I accidentally mixed up a few cables around last time, which shocked me during the calibration setup.
I'm in the market for this product specifically for my personal PC where I'm at 90% of my work & free time. I've been heavily debating whether I want to add something like a RP-600M + Marantz NR1200M or get a set of Sevens or Nines for my PC. I'm particularly concerned about the input lag if I do the receiver route because I play a lot of computer games and audiophiles are quite a bit of a different market compared to competitive gamers which is very common among the younger generation. For home theatre, I already run a 7.2.2 setup with a Klipsch Reference Premiere lineup but seeing how little time I actually spend in my living room I'd like to bring that enjoyment to my computer setup where these products seem to match my needs much more. On a computer desk, there is very limited real estate so removing a receiver box would be very very valuable. This is how I was planning in arranging the speaker setup.