Personally I see both sides on Riviera - those who find it to be a beautiful resort and one of their favorites, and those who find it one of their least favorites.
For me, I always enjoy visiting the grounds, the restaurants are great, bar is great, service is top notch, everything is beautiful and luxurious. I go there nearly every vacation to Disney and eat there often - both quick-serve and Topolinos. As a resort (unrelated to Disney), it's top notch.
At the same time, I don't really have a desire to stay there on
DVC points, because it's less 'Disney' than other choices, and I do like the immersion and theming. And I get that the 'theme' is French Riviera - which it nails, but it has less of a 'step into another world or period' kind of immersive theming. I find the theme to be more 'luxury' than any actual sense of place or period. Lovely in general, but not so much of the Disney-ish feel.
My kind of theming isn't IP-style, like Art of Animation or Pop Century - they're wildly themed to products, decor, or kitch, etc. MY favorite resorts at Disney World are Wilderness Lodge and Animal Kingdom Lodge...like stepping into another state or country, everywhere you look. I enjoy Boardwalk and Grand Floridian's 'period' theming, Polynesian (not the new tower), French Quarter and Coronado (good transporting theming doesn't have to be at Deluxe resorts). I even like Old Key West's theming - everything from the music to the boat transportation to DS and the colorful bungalow designs does give me Keys vibes. Riverside has multiple themes going on, but all are centered around Gulf-coast southern styles - bayou homes to plantation estates. Fort Wilderness' old west town feel.
Pretty much all of the newer resorts and buildings are beautiful, and many have great restaurants and service, with amenities and luxury looks that match fine hotels around the World...but they also often feel like they could just be a higher-end hotel in any city in the world. The theming part is not really something Disney has been doing lately with buildings like BLT, Riviera, Gran Destino, Island Tower, and Lakeshore Lodge. They'll throw a few colors, or a few flourishes into the overall design, but they feel like any city hotel with a few add-ins to try to look more like the surroundings. The lobbies, restaurants, common rooms, a lot of the grounds, and the villas/rooms themselves are much more generic and unthemed. Of course, similar criticism even at the very highly themed resorts when they get room makeovers, they're very much neutralizing the intense theming and going more trendy renovation / house-flipping look. I still enjoy staying there, find the rooms all very nice, but I miss the all-immersive theming styles they used to have, because I didn't want Disney to feel like my other vacations around the world.
I'll be at Boardwalk in September, and will very likely be over at Riviera, grabbing some drinks and getting a meal at Topolinos...I love visiting these newer resorts but have no great pangs to stay there.