Dedicated Vinyl system next upgrade?

Hi. I love my system. I really do. I love vinyl and listen to vinyl nearly exclusively via “appointment listening”. I do Sometimes stream and listen while I walk or while working but I love just sitting and listening to my stereo. I believe I’ve arrived regarding finally achieving a great set up and have experienced that vinyl “magic” that audiophiles obsess over. I understand that limitations exist and a great stereo will reveal the quality of a recording - good or bad. The law a diminishing returns regarding  upgrading is something I’m mindful of. I don’t have endless funds to spend on upgrades. My question is - what should I consider upgrading next? Should I ditch the integrated amp considering I’m using an external phono stage? Or should I go with a better integrated amp? Or should I look at a better cartridge? Do I upgrade my turntable or just the tonearm? Do I upgrade the power cable on my amp? 
Here’s what I’m currently working with - and thanks for your thoughts/suggestions! 

Clear Audio Concept Turntable
W/ Hana SL cartridge 

Herron Audio VTPH-2a Phono Stage

Rogue Audio Cronus Magnum II integrated power amplifier 

Kimber Kable speaker wire and interconnects (I forget which model - an entry lever set - nothing crazy) 

Bowers and Wilkins 805 D3 stand mount loud speakers

Set of two stereo REL S/510 subs

The room is 18’ x 30’ with a high vaulted 18’ ceiling. I do not have any room treatment. This is a tricky area for me. Interior aesthetics are important to me. This is both a living area as well as a listening room. I truly hate the idea of hanging RT panels on the wall. I might be able to live with some corner bass traps but my original goal was to build a system that sounds great without making my home look like a recording studio. I understand this poses huge limitations but that’s the deal. I do have my speakers out and away from the back wall. I have played around with speaker/subs placement as well. Thank you all for the great thoughts/ideas, keep them coming if you want but again, I’m not hanging RT panels from my ceiling.
As in a previous response, buy records from 50' & 60's and some from early 70's... also grab the record Dr record cleaner works great if u don't mind spinning the record manually. Buy a good cleaning fluid to go with it, non alcohol. The audio intelligent #6 is a good product. I would not change out either the turntable or the hana cartridge, I think you have done great there. The hana are terrific cartridges for the money, I run the hana el and I love it. I'd go with maybe a nice power conditioner along with at least a high current power cable for the amplifier, maybe try the audioquest thunder and the audioquest Niagars conditioner. Also maybe try a few different interconnects from chord, Atlas, Qed, ecosse....yes I'm partial to UK interconnects lol. 
NP thanks for the clarification. Then we know that you have reached your maximum of treatment as I said before. ;)

Then it is time to measure and identify issues and solve them with a little DSP in the signal path between preamplifier and power amp/s. With that solution you do not need to put any sound treatment anywhere.
  • Better integration between sub/s and speakers by:
  • > by be able to compensate distance/time difference between sub/s speakers.
  • > by be able to use Lindquist steeper x-over filter that he also advocate for.
  • Adjust the unlinear frequency response of your speakers (all speakers has that more or less) or maybe there is a dip that you like.
  • Adjust for unlinear frequency response how your room interact with your speakers.
  • Being able to adjust for "Equal-loudness contour" (Fletcher-Munson curves or international standard ISO 226:2003)
  • Being able to adjust for your own preferred sound preference.
Probably something that i have forgot..

Regarding the integration between sub and speakers.. I am able to turn off my bookshelf speakers. And only listening to the subwoofer. I got very surprised when I could hear faint in the background when the subwoofer were playing the sound of the singer and other instruments that is higher in the frequency range..
And the cut of frequency were at the lowest setting at 40 hz!
I should not be able to hear a singer at all. I suppose the implementation of the knob on my subwoofer were using a shallow x-over slope perhaps max 6 dB/octave.
But with the DSP doing its job and I use 48 dB/octave at 53 Hz. Now the problem is solved with that the subwoofer will only amplifie and play those frequencies it should and nothing else.

I guess I am on optimize's side in this with a few caveats. Room control will correct frequency and time issues better than any other method by a long shot. But, it will not change the way a room sounds. It is not eliminating reflections or preventing echo. It's time correction is purely between drivers and subs. If you have a reasonable room and sub woofers set up correctly room control is all you need. Unfortunately, this is usually not the case. In the bass if the nodes in the room vary widely the power required to correct them will clip amps and bottom out woofers. With two subs if you put them right up against the wall or in corners symmetrically placed around the satellites you can minimize this. With one sub you can forget it. 
Most people do not understand that room control is done at very high resolution with high bit density. In my unit it is 48/192. Resolution this high is invisible, vinyl sounds just as vinyl always sounds except better.
I am working on pictures of my system including shots of the computer screen with measurements and corrections for the virtual systems page. I am having a hard time capturing the screen without haze so, if anyone more skilled in photography has any ideas they would be greatly appreciated.

Paul, if you go for a new tonearm I might suggest in order of expense the Origin Live Zephyr, Kuzma's 4 point 9 and finally Schroder's CB. Before you buy any tonearm please check the spindle to pivot distance and make sure the pivot will land squarely on your tonearm board which is not very large. Again, in terms of bang for the buck just changing the cartridge to one that is more compliant than the Hana will make the largest improvement in sound quality and eliminate some of your woofer pumping. I always assume people are using a full 2 way crossover for the subs. If not, getting a proper 2 way crossover will stop woofer pumping dead and drop distortion in your satellites by an order of magnitude. It will also allow you to raise the crossover point and make seamless integration easier. 

Back to room control, if you think the frequency response of your system is reasonably flat you are sorely mistaken. Unless you have room control This is a generalization I am more than happy to stick to. If you get a calibrated mic and impulse testing program, ,you will see aberrations over +- 10 dB. Your fequency response curve will look like the rocky mountains. I have ESLs and I will show you all their response curve once I get the photography down.