Musical Sound Quality of AV Surround receiver vs. pure Stereo


Running Linn LP12 turntable, Bluepoint No2 stylus, with Jasmine phono pre-amp, Marantz sr5008 with B&W 685s2 on LR fronts with 686 S2 LR surround,  Paradigm CINEMASUB Cinema Sub 300W Speaker.

3 questions; 1) While I canceled out the center channel (using Marantz Audyssey setup), I am playing 99% from my turntable and CD player (Yamaha w/ DAC built in). The depth and spacial separation of the music is uncanny, but difficult to phase given it is being played in a digital (Music setting) format from one of the settings on the Marantz receiver. When I switch to pure stereo, the volume has to be turned up and the depth of the soundstage just isn't there. Would upgrading to a more powerful and musical integrated amplifier help (i.e. Anthem  Anthem MRX  720?) help with its killer room correction or 2) Do I look for a 2.1 integrated amp or tube amp to compliment my B&W 685S2's and sell the 686's or 3) do I just bite the bullet, look at a traditional good integrated amp or tube amp for around $3K with $3K Audio note AN-K speakers. Traditional sound....

Thanks, I am new to this group and have read a number of discussion threads. Obviously, a lot of you are infinitely more knowledgeable than I am, so any and all replies would be greatly appreciated. PS No man cave, this system is in my living room, so the wife is a little particular about too much gear ! Thanks everyone.
128x128phill55
The sub looks to be self powered so no concern there.  The first question you need to answer is if you like the 685s enough to keep them.  If yes, then almost any decent integrated stereo amp should yield a significant improvement over your AVR.  The Outlaw should work fine and is a good amp for the money, but it's not up to the standards of the Hegel IMHO (or probably the Krell either, but I'm not familiar with that unit). 

If you're upgrading the speakers, wait until you figure out which ones before upgrading your amp so you make sure they work well together.  A lot of people like Audio Note speakers, but they're quite different from B&Ws and there are lots of other great options out there.  Hope this didn't just confuse things further. 
Is the Hegal an iij integrated amp which CNN accepts a powered sub woofer? Thanks,
Sorry hate auto typing. Will the Hegal accept a powered sub woofer? I thought it was pure 2 channel and I know from the Marantz that the sub woofer digs a little deeper than the b&w 685's by themselves. Thanks
I use the same speakers (L+R) for HT and 2 channel, just switching out speaker cables. The 2 channel amp is better. But, that said, I could live with the HT receiver in pure direct mode if I had to. The difference in amps, contrary to what some say, is quite minimal.