First, they may not keep the trial going a full year. They've changed course before.
Second, it's 4 out of 20 but that doesn't tell the whole story.
Take AoA. It's the only value resort that has rooms for 5 people. It's also, arguably the nicest.
POR - shares facilities with FQ so I'm counting them as one. Also the only moderate that sleeps 5, and the only moderate resort not under construction at the current time. So if you have a large family, or just want to stay in a moderate resort not under construction, you're out of luck.
YC - shares facilities with BC, so count them as one. Best pool in WDW. Limited choices if you want to stay near Epcot.
20+ hotels technically, but if you combine shared facilities, and take out DVC, you end up with 16 (inclusive of Fort Wilderness cabins). So that's 25% of the options, and some of the best options IMO, off the table for people who don't want to be around dogs.
For me, my favorite hotels on property are AoA, POR/FQ, YC/BC, Poly, and GF. So that's 3 of my 5 favorites taken, and the only two remaining are pricier.