Hi Fishcall,
I believe the DNA 0.5 is rated at 100wpc and the DNA 1 at 185wpc, so I'm pretty sure the either McCormack can drive the Paradigms quite well.
The 3802 is designed to drive multiple speakers for a home theater. Many more compromises have been made in its design in order to accomplish this. A good two channel amp, the McCormack just being one example, is made with less compromises and designed to drive just two channels. Without going into detail they really are worlds apart.
Please don't think a McCormack is the only amp that might help you achieve your goal. Although I've never owned one, I've heard them and have been impressed. It just seems to be a very good candidate within your budget. Plus, there are many happy past and present McCormack users here on Audiogon.
The Plinius 8200 integrated is also a very suggestion. Its rated at 175wpc and if it's like any of the bigger Plinius amps I've heard, it's very smooth, powerful and has a touch of warmth. It combines the preamp and amp into one chassis and would save space over having separate components.
Either of these would be a big step over the Denon. If the 3802 is sonically similar to my friend's 5700 I remember it being a bit dry and thin sounding overall. It wasn't very dynamic either.
I can understand your hesitation to spending all this cash on gear you've never heard, especially if want to retain HT capability. I tried doing the same five years ago and found that I couldn't be satisfied with an all in one system. I eventually started a second stand alone two channel system.
Whatever you do, don't jump into anything right away. Do more research and save enough money to make a BIG step which will hopefully also be a noticeably improved one.
Good luck.