Riviera is awesome as a resort, and I'm sure Poly2 will be great as well.
But I think Riviera, Poly2 and everything else going forward will be a tough sell given the resale restrictions. Yes, the extreme fans (or uninformed buyers) will buy direct regardless of restrictions but it's a big leap to say that a large part of VGF sales volume from June, July and August will now go towards Riviera. It looks like they sold 40K-44K Riviera points in each of May, June and July (we'll find out August soon enough). It may do better in the fall, but let's see just how better it does in Sep and October, now that it's the lowest priced WDW option by far (Sep will still have residual summer sales closings).
Riviera resale prices today are not where they will be in 4-5 years. Yes, some contracts sell because some some buyers are willing to pay higher prices (Econ 101 - demand curves generally slope downwards), but most contracts linger out there at an impasse for months with the sellers not budging. There are 39 contracts out there with 300 points or less - 23 of those (~60%) have been on the market for 60+ days and some as long as over a year. It's not an efficient market...
The resort is barely 3 years old and not even sold out. Supply will increase substantially in the coming years, the market will become more efficient, and resale prices will eventually settle at whatever buyers and sellers view as "fair value" down the road. IMO, it will be much lower than today which would make it that much harder for many informed buyers to buy direct. That said, I do think it's a great resort and would not hesitate to buy it resale, but at a price that reflects both it's extremely limited functionality as a resale product, and it's higher dues relative to other resorts like Poly1, VGF, and BLT.