In your (expert) opinions, what non-Disney on site hotels are the BEST compared to other Deluxe Disney Resorts? Theming, Convenience to Parks, Guest Service, Pool(s), Restaurants, etc…
There are really only 3. The Swan, the Dolphin, and Shades of Green (SoG), the DoD resort. I haven’t stayed at either the Swan or the Dolphin so I can’t speak from first hand knowledge, but from all that I’ve read here the rooms and amenities are similar, the prices slightly lower, and the Disney theming virtually non-existent. But you can walk to DHS and EP. I have quite a lot of experience at SoG; if you qualify to stay there I can fill you in.
Darn, I thought the bonnet creek hotels were on property (in the bubble) as well as a few near Disney springs that were non-Disney (ex. B Resort). From the research I have done, I don’t think we would enjoy our stay as much but it was worth asking. 
The Wyndham Bonnet Creek is basically across the street from POFQ. So, I’d consider that in the bubble. There are others in the immediate area too.
The Four Seasons and Waldorf Astoria - they are on property but a world away. You have to consider them “off site” though for transportation and EMH etc. Bonnet Creek is on site (actually an island that isn’t disney land) but hey surrounded by WDW is pretty cool. However to what you are probably wanting (as far as the convenience of on site - Swan / Dolphin are the only options unless you are military.
Stayed at Swan - I would NOT compare it to a deluxe - especially the pool. Did Swan over Dolphin as Swan has queen beds and is a bit smaller. Loved the location, hotel itself was ok. Paid 100% with points so no money out of pocket. If I paid more than $200 / night I would be upset
So what exactly are you you looking for - what conveniences etc of an “on site” do you want.
NONE will have the theming that you may want - however for me the theme of a beautiful hotel is fine by me. SWAN / DOLPHIN offers EMH and has pretty good Disney Transportation. No other hotels (believe the HITLON at Downtown does though will offer EMH. So if EMH is a deal breaker - your options are limited.
However all the other ones, bonnet creek, Four Seasons, Waldorf all are close - but you will want a car and do not (To my knowledge) offer EMH.
None of these in MHO are really a deal breaker though
Bonnet Creek is technically on site. And it gets good reviews. You can really score some good rates there as well. We were looking at a 2 bedroom presidential suite for under $200 a night. They do have shuttle service but you do pay each day to use it. Easier just to rent a car.
We were contemplating a last minute trip because we found really cheap nonstop flights. Unfortunately the deluxe disney hotels have either no availability or sky high prices. I was hoping for a happy medium with a luxury non-Disney hotel that was still in “the bubble” but I think we are going to just wait. 
I’d do a Disney moderate before canceling the trip 
I’ve stayed offsite at a Disney Springs hotel, Wyndham Garden Lake Buena Vista, and it was fine for a budget trip but they tack on things like the shuttle/resort fee that you can’t remove, could only recommend if you’re looking budget and moderate is too much.
I would love info about SOG. We are visiting in December. My biggest questions are about transportation and if it is faster to walk to Poly?
The answer to that is “it depends”. SOG busses run at specific times. If you catch the SOG bus, it’s probably faster than walking to the Poly. If you miss the bus, the Poly is a 10 min walk. For MK and EP, the SOG bus takes you to the TTC, and you use the mono or ferry from there. The other parks and DS have direct service. Sometimes coming home from a park, instead of waiting for an SOG bus I’ll grab one for the Poly and walk back (frequently with a drink from Tambu in hand).
Thank you!
My daughter and I stayed at Bonnet Creek Wyndham this past February. We loved the proximity- VERY close to Epcot and HS. While not a Disney Resort, certainly would say it’s on site- they offer transportation to the parks but very limited times and charge for it. We rented a car so that was moot. We enjoyed it- I’d stay there again if I had a car. I bedroom unit, view of Epcot Illuminations from the balcony.