DVC surveyed members about potential locations about 3-4 years ago and Caribbean was one area highlighted. Others were Vegas and Lake Tahoe.
Any (near) future non-park developments will be entirely dependent upon Aulani's performance. And reportedly they have struggled with Aulani.
Biggest challenge is actually convincing members to buy into these non-park locations. Aulani has been a very popular destination for non-owners who book at 7 months, but convincing folks to buy in for the 11-month priority year-after-year is not so simple.
Financially, off-site resorts are much more costly to develop and maintain. With Aulani, Disney spent $120 million on the land alone. By comparison, building at Walt Disney World or
Disneyland costs nothing for land.
When they add-on to existing WDW or DL resorts, they often do not need to invest in more parking lots, front desk facilities, bus / monorail / boat stops, etc. Additions to pool facilities or other recreation are modest. Offices, storage and other infrastructure for housekeeping, maintenance, management and security is already in place. When they build off-site, all of that must be created.
Vero and Hilton Head were both considered disappointments in the 90s. Took about 15 years before they decided to try again with Aulani. Barring some explosion of demand for Aulani points, I just don't see why Disney would choose to put more money into off-site projects rather than Poly, Ft. Wilderness, Disneyland Hotel or any of a dozen other on-site options they've kicked-around.