Ideas to improve my system

TT/Phono/Cartridge. Last! Next Year!

I agree, by all means keep an AVR and surround speakers for any Video based program.

Then improve it for everything: Movies; Video/Music Programs; or Music only (via Web, Cable, Media) via a separate ’FRONT STEREO SYSTEM’

You need

1. FSS. ’Front Stereo System’ with ’HT Bypass Input’ to receive the AVR’s line level Front Signals.

2. AVR with ’Pre-Out’ for the AVR’s Front Channel line level signals to be sent out to a separate ’Front Stereo System’.

FSS Always drives the Front Speakers. AVR always drives center and all surround channels.

I had it backwards, it became very clear here:

https://forum.audiogon.com/discussions/avr-internal-2-channel-audio-mode-or-ht-bypass-external-equip...

Critically: AVR ON, it controls the Volume including the Front Volume the FSS is amplifying.

Unfortunately, your Sony AVR does not have ’Pre-Out’, fortunately many do, and HT Bypass is gaining understanding.

There is some yap about any chosen AVR’s pre-out signal strength

https://www.avsforum.com/threads/receiver-brands-with-the-best-preouts.3045816/

Anyway, think LONG Now, think best 2 channel sound, then figure out how to use that for your HT Front.

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Bass, Subs: improved bass, make sure it is part of the Front Stereo System IF you want extended bass all the time, even when AVR is off, (large mains, or stereo pair of front firing subs adjacent to smaller mains)

or part of AVR Only, i.e. Single Sub movies only, Dinosaur Stomps ....

I think your Klipsch and B&W center probably sound good together,

 however,

the sensitivity mismatch probably needs a somewhat large adjustment in the AVR.

for that reason, I would start by changing to a Klipsch Center with matching sensitivity, Klipsch can advise you, there seems to be a sale going on. 

I suggest this one, it's ports face forward

https://www.klipsch.com/products/r-34c-center-speaker

Do you NEED more Bass? 

WANTING more bass seems obvious to all, but you know what you are getting now.

When you consider new AVR and New Integrated 'Front Music System', consider if 'more bass' will be for

AVR use only, i.e. single Sub adding Dinosaur Stomps,

OR,

Extended Front Stereo Bass (two front facing subs, near the mains, always on. 

look at this batch of used Klipsch HT Speakers

https://www.ebay.com/itm/203529373861?hash=item2f634bc8a5:g:BkYAAOSwCSBg9JIN

Sensitivity-Efficiency is volume/power. You get a sense of the PROBABLE amount of attenuation (less or more) you will need when you mix and match.

Frequency response is quite another thing, I suspect your Klipsch Mains will also ’blend’ both volume and frequency characteristics. You don’t want specific frequencies jumping ’out’ or ’in’ from l/c/r. I would try that change FIRST, then go from there.

My separate 2 channel system, ’other end of the room’

https://systems.audiogon.com/systems/9511

I use Two L-Pads in each speaker (vary attenuation of mid horn to woofer; vary attenuation of tweeter to mid horn. Hard enough, then VERY HARD: I have to very carefully match L to R

so Casandra Wilson’s Voice doesn’t move L or R of Center, or certain Piano/Violin frequencies shift this way or that, that’s a no no. Takes weeks of decisions playing all sorts of music. Ah, when done, awesome. Don’t forget, this is done IN MY LISTENING SPACE, not some factory average design for imagined unknown spaces.

I just made an offer for one of those Klipsch R-34C Center Speakers (used) for myself. It will be too efficient, my DBX Soundfield 100’s are ’only’ 91, so I will likely be cutting the center channel signal output in the AVR. Except, my Mains are near corners, and use special ’crossfire’ angles (like large toe-in), so who knows? Frequency Blend? I can return it, I’ll risk the return shipping cost.

Back to the old big CRT days, I’ve been happy with the little Bose VCS-10 which fits anywhere, including behind a CRT inside a wall unit with receding doors way back when.

I have more room now that I chopped my big wall unit down, put my Monitor on a Glass Shelf on a 7" Riser I built with some of it’s solid cherry wood, the Klipsch fits, right at seated ear height (no rear ports).

back to attenuation: My rear surround speakers are small directional speakers, Paradigm Micro v.3. I still remember the surprise when I first heard them at 6th Ave. Electronics.

https://edsgoodstuff.com/edscart/index.php?main_page=product_info&products_id=7559

laying on their backs, firing up, using the 6" wide space between the back of the sofa and wall behind like a horn, so their efficiency/output is what it is, then attenuated in the AVR. (I stuffed some foam in their tiny rear ports).

All these years I just do the volume adjustments in the AVR, done, good enough, no room correction like you do. I reset occasionally, do the basics, I forget all the damn options, just adjust vol then use either Direct; 5.1 or 2 channel. I occasionally find forced 2 channel sounds better, there's a lot of crap mixes out there, and who knows what studios/cable companies are 'thrilling' us with.

My Single Sub, 1,000 watt Velodyne, is adjacent to me (see photo), fires facing the front opposite, crossover and volume for my viewing spot. Off for Direct 2 channel or forced 2 channel, the DBX have 12" woofers, plenty except Jurrasic Park, Black Hawk Down.
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I hope you have discovered this movie, Domino, with an awesome kick-arse sound track.

https://www.imdb.com/title/tt0421054/

I bought the used Klipsch center and the two small speakers.

https://www.ebay.com/itm/203529373861?ul_noapp=true

He still has the pair of subs, if anyone is interested, 'contact seller'.

Not sure, perhaps ask him to find their model #.

I wrote this seller, his personal nearly (4 months old) new klipsch center

https://www.ebay.com/itm/124782709100?epid=10025586026&hash=item1d0da1096c:g:RLUAAOSwS35g0k9L

he said he did not register the warranty. I asked, and he said if disaster struck, he would cooperate to use the 5 yr warranty he gets