I think you'll find that the general concensus (with a few notable exceptions) is that the reciever doesn't really make a difference with regard to warmth or, ahem, brightness. Many people here love their Denon+Axiom setup, so I wouldn't worry about that. I think the 3802 is a fairly recent model, correct? if so, then I wouldn't waste the money "upgrading" to an H/K. Also, the 7200 is getting a little long in the tooth, feature wise, so you might want to look at something else if you've decided on getting a new receiver.
Having not heard the Polks, I can't say if the M22s are better, but see if there's anyone in your area who has them and is willing to let you audition them. There's a long running thread at the top of the Questions and Comments board with people, their systems, and where they are.
I didn't do it, no one saw me, you can't prove anything.