All of the things you list are possible to fix ( probably the undesirable resorts is the hardest but add a lazy river to them and bingo)
But I see no reason that spec renting would have any significant effect unlike fixing the point charts.
Even if all the new owners of the ex-commercial owner points book SV rooms, at least the rooms will be used by owners and not renters. I think that is good for the membership as a whole. I think the entire point of DVC is for members to book vacations using their points for themselves and their families. Not for a broker to buy up thousands of points and book cheap/in-demand rooms and sell them for a profit.