MFs at Riviera will in all likelihood remain somewhat steady (or maybe even decrease slightly) over the next few years while the resorts that are currently in the $7+ range will be approaching the Riviera level over the same time frame. Unfortunately, MFs for aging resorts can only go up.
I'm not one who needs to own points at every
DVC resort and since i can use my existing points to stay at Riviera, I don't think there is a realistic price that would make me change my mind. However, I do think it's one of the nicer DVC resorts and would have already purchased regardless of price and/or restrictions if I were in the market.