If you want far superior, you should be looking at speakers, not amps. Denon and Marantz (and NAD) all know how to make good amps and they didn't forget when they started making AVR's. Of course, AVR's do allow you to screw up the sound in many ways, so you have to be up for the learning curve.
I will agree that if you have demanding speakers (like inefficient 3 ohm speakers) AVR's will be brought to their knees in short order! Of course, so will most stereo units! However, in that situation you can probably only find the capability you need from a stereo Amp because there are limits on what you can fit (and keep cool) in one box (and what you can draw from one 15A outlet).
Have you actually compared good avrs to good stereo amps?
Ok, now i am at a computer with more time on my hands...
From my experience:
I started with surround sound somewhere around 1995, with a NAD pre-amp, whitch never gave me anything decent (i was to young to understand how things should be set up, also the surround sound at that time was not all that good). Somewhere around 2000 i got a Denon avr introducing Dolby Digital, but still with manual calibration (cannot remember the model) this had somewhat better soundquality, but was never great.
All of the above was in various livingrooms as we moved a little bit around, but from now on we are settled in our own self-built house
Then around 2011 i think, i got my first Audyssey avr, the Denon AVR2313 ($700 range), this was a great leap in surround sound duo to auto calibration (i still did not understand how this should have been set up, nor the interrest to find out), however stereo sound with music was never any good.
Last year we stopped renting out the basement, and the possibility for a dedicated home theater opened, so time to start shopping!
I stumbled across a used Hegel H80 stereo amp with a good pricetag ($700, new price around $1500 here in Norway) since my living room now would be a dedicated stereo setup this seemed like a good choice, and boy was it!
It really brought my Bowers & Wilkins 683's to life, with sound and dynamics i did not know they where capable of, i could simply not belive how much better it sounded!
This in spite of the rated 80W compared to my AVR's rated 105W...
At this point i really started to read and find out how things actually worked, and why things can sound that different, so after a while a decided to get my HT up and running on my budget and desired quality i would need to build speakers myself.
So i built a pair of ER18's finding the plans on this foum.
This speakers are known to be pretty efficient (as opposed to the B&W's) and can be driven by pretty much everything, the Hegel amp drove them to perfection, sounding way better then the B&W in my livingroom.
When they finally where moved in to the HT after the room had been completed i used the AVR2313 on them, and where never happy with the sound (some room related, and some electronics), to make things better i built some Hypex amps (2x60w @ 4ohm) for them, but it only made the sound slightly better, i also borowed a huuuuge Parasound from a friend (i think it was rated to 250w pr channel), this actually sounded just like the Hypex amp, so i can conclude that the problem is not the power amp, but the pre-amp or DAC in the 2313.
I have also tried the Hegel in my HT and it was a different ballpark.
So now recently i got a Denon AVR X6200W on sale (paying $1300 for a $2000 amp) and it sounds way better then the old 2313 whitch was also a good avr, but still not as good as the Hegel.
This is now in a acoustically treated room.
As i dont know Mrboat's amp specifically, i would say by the model number it is a fairly old avr, and have no problem to conclude that a decent stereo amp would out-perform it easily.
I agree that speakers may prove to be the biggest change in a system, just next to the room itself ( do a bit of reading on room acoustics and you know what i mean), however the amp and DAC is also a really big contributor to a great sound.
Sorry for the long post (also slight offtopic) and for my poor english (obviously not my native language), but now you can see where i am coming from and what i mean with the new amp comment.
If you have a nice dealer nearby (or a friend with a decent amp) just see if you can borrow one home for a demo and listen for yourself.