I feel like if that's the case they're gonna outpace what they can sell. I don't know how much of the poly has sold, but there's so many more units they have to sell off at copper creek and now riviera? Will be really interesting (nevermind the aulani points still sitting there)
Poly will be sold out before the end of 2017. That gives them about 18 months to exclusively sell Copper Creek before they start pre-sales of Riviera.
Copper Creek has 184 rooms and cabins representing 3.3 million points. That's fewer points than Poly. Poly has sold about 1.7 million points over the last 12 months. If Copper Creek were to equal that pace, it could be pretty close to sold out before Riviera comes on line. Of course that will be a major challenge. An overlap of 6-12 months is more likely, but not terribly unusual. Offering buyers choices isn't necessarily a bad thing.
Disney probably did jump the gun on Riviera by about 6 months, but I have a feeling Star Wars is driving that. They need the gondola system operational before Star Wars land opens in fall 2019. And Riviera is a key station on that line.
I think Star Wars will help sell Riviera points so it's not necessarily a bad thing. DVC has had worse overlaps in the past. If memory serves, back in 2008/2009 they were selling at least 4 resorts simultaneously (Saratoga, Animal Kingdom, Bay Lake, Grand Cal.)