Although a boat-based attraction would also contribute to the eclecticism of DHS's attraction lineup, if they wanted something "faster," IJA has shown incredible staying power as a top-tier attraction for over 20 years at Disneyland (although I prefer the DisneySea version, because the Disneyland version relies a little but too much on blacklights against 2-dimensional backdrops, but presumably a WDW version would be "modernized," so I'm not worried about those issues with the Disneyland version being copied). Adding a version of the Paris roller coaster / Raging Spirits (or a more kid-friendly, non-inverting version of the same) would make it a really solid mini-land.
Shanghai POTC tech for an Indy boat ride
Raging Spirits roller coaster as a second ride
"archaeology site" play area for kids
Now you have a nice land.