The best romantic getaway rooms at WDW are the cottages listed as “Outer Bldg - Garden Room - Club Level Access” at the Boardwalk page of Disney’s website. $896 value dates to $1445 on Dec 25th.
Walking around the Boardwalk and Epcot Resort Area gives you access to the best restaurants and bars for couples without kids, plus a romantic walk to Epcot.
Huge bonus: you get a second half bathroom in the room, too.
(While it’s definitely a romantic atmosphere, the Polynesian can be a Minnie Van excursion to Trader Sams, the Luau, and a walk along the water by tiki torch light... then return back to the Boardwalk to sleep.)
POFQ is the most romantic moderate. Boat ride to Disney Springs and horse drawn carriage rides.