OP,
I think you will find the vast majority of audiophiles still require/use a preamplifier, even if they do not have an analog end. The straight from source to amp requires equipment that is exceptional and compatible. My guess is 90%+ have not been able to pull it off and have gone back to preamps. Unless, you are incredibly experienced and willing to swap all of your electronics I would not try it. You are likely to end up with dry analytical sounding sound.
The really important decision here is the kind of sound you are looking for. Extremely detailed, or detailed and musical. Let me put my 2 cents in here. You probably want musical… tremendous details sound with slam like a great thing… but it frequently lacks the emotional connection most folks actually crave.
As far as keeping the Denon. Ok. But mixing HT and audio generally kills the audio side. Compromise is on the side of audio, They have two different objectives. If there is any possibility of separating the functions… I would recommend it. I would rather have a tiny separate room for my audio system then be able to spend 5 times more and combine them. I have heard incredible systems in rooms the size of a closet and horrible combined HT / audio systems costing many times more.