My impressions:
1. The queue looks great, almost on the level of the Indy queue in Disneyland. Really helps the overall appeal of the attraction, but is sort of overdone when compared to the ride, and bit more realistic than the cartoon world of the ride. You also don't see Eric's castle from the queue, and even the "figurehead" Ariel seems to be too high up for guests to see very well.
2. They really improved the subermersion scene in that they project the bubble effect above the clam shells, DCA's version doesn't have this. Just a project on the back of the clam shell in front of you. Major improvement, IMHO.
3. Ursula's lighting is much better done, i.e. her whole face is actually lit up, and it turns a brighter shade of green when is casting a spell, I feel like this is an improvement as the lights in DCA's version don't illuminate Ursula nearly as well, (her face is sort of cut-off in the light). Really improves the overall scene.
4. Triton's beard/eyebrows are fixed, i.e. his eyebrows are white don't look like brown animal fur glued on him like at DCA.
5. The Kiss the Girl scene has the old lighting they used at DCA which didn't work, i.e. bright lights on Ariel/Eric, which make the plastic "water" the fish are spouting look all the more fake. I believe they changed this at DCA so that the light is more bluish and looks more like moon light. MK's version has no moon! And you can't see the trees/moonlit night. Small changes here would greatly improve this scene, I am guessing because it is a soft opening not everything is working.
6. They added little reddish explosions around cut-out Ursula, and this one does more than sway slowly, looks less cheap than what they have in DCA, but still looks sort of phoned in. I can see they did this to draw attention to the cut-out Ursula as guests were missing this little thing in DCA's version.
7. No duplicate dancing turtle in the final scene. Don't know if this was done for artistic reasons or b/c they are still working on the scene.
8. The plastic fish mounted on the wall going to the big "Under the Sea" party was given a plussing by adding Triton's under sea castle in the background with some dynamic lighting to liven up a scene which is motionless. In DCA's version there is just a bright greenish light. I would say it is a good plus as the rides are overall short on details like this.
9. Not sure that it works having two Scuttle at the beginning of the ride, one in the queue, and one in the first scene. Besides have two scuttles in close physical proximity, I think it sort of wears out Scuttle's welcome.
Everything else is pretty much the same, i.e. duplicate plastic fish and animatronics, and a big pet peeve of mine is the fish mobiles with plainly visible "bars" holding the fish up. I feel that the inside of the ride didn't get the same attention to detail as the outside, but you can tell that somebody working on MK's Mermaid is making an effort to improve the little things, unfortunately the last half of the ride is screens, cut-outs, and liberal use of duplicates and is sort of boring.
My report card:
DCA's Mermaid
Queue: D-
Inside Ride: C
MK's Mermaid
Queue: B+ (Would have given it at leas an A- if Eric's castle was better, i.e. more plants and towers and windows, looks like the Cliff Notes version. And while Indy's great queue meshes seamlessly with the ride, Mermaid's queue is done so well that guests are thinking they are in store for a bigger treat than what they get).
Inside Ride: C+