The demand for Disney cruises will not go down with new ships coming on board.
The demand will remain solid - with some possible seasonal lulls.
But,
DVC isn't going to drop the number of points - it just doesn't make sense for them or for members.
The ability to exchange points OUT of your home DVC resort is a member perk - and not at all guaranteed anywhere.
Cruises aren't a bad use of points, it all depends on what time of year you choose to go. If you are going on a cruise in mid-summer - YES it isn't as great of a price as a villa or paying cash for a cruise. Cruises CAN be a very good use of points.
For someone that owns a minimal number of point (160 or so) a Cruise is a bit out of reach for a family. But, for owners that have 500+ points - a cruise is another great vacation option. Cruises are all inclusive - so when you calculate your cost of a week at WDW (Food, tickets, extras) and then calculate the cost of an all inclusive cruise - you'll see that yes, you may be spending more 'points' - but overall you are spending less cash.
So when someone says that cruises aren't a great use of points - it all depends on a particular person's use habits - and how they budget.
Is cruise pricing via points fair? I think it is.
But anyway - back to inventory - The Wonder is now in its permanent home - the Dream is now it its permanent home - but the Fantasy will come online - and that will push the Magic somewhere. Disney isn't likely to keep the Magic, the Fantasy, and the Dream at port Canaveral. It will be moved - so the inventory overall out of Port Canaveral will increase some - but it will increase to back fill the demand that has always been there, especially for peak summer seasons and holidays. Disney isn't going to have trouble filling their ships - it hasn't been a problem, and I don't think it will become one.
Should DVC and
DCL partner up to fill available inventory when it exists - ABSOLUTELY! If DCL sees that at 6 months out they have a specific off peak season sailing that is only at 50% capacity - I think it would be wise of DVC to step up and offer some promotional point reduction for a specific sailing to open up some summer and peak inventory.
There are a lot of balance variables that come into play - and fractional ownership - especially without assigned use weeks - it can be like the game of giant block Jenga I saw played in Diversions Lounge on my most recent cruise! HAHA