The Gaudi comparison is quite apt -- from the reliance on sinuous lines to the use of color... even little details, like the employment of broken ceramic tiles for some of the land's ancillary exterior trappings. The most specific reference would appear to be the Casa Batllo -- my favorite landmark in Barcelona -- which, even to the architecturally uninitiated, has a distinct aquatic demeanor.
Although the outside of Mermaid Lagoon is undeniably more abstract than a simple, literal translation of the animated movie's environments, I personally didn't find the effect overly distracting. Part of that is probably due to the fact that I give theming that is both aesthetically ambitious and executed at a very high level a "pass." For example, although I tend to be extremely picky about "off model" depictions in the parks, I'm more than OK with Dorothea Redmond's stunning tile murals in Cinderella Castle, despite the fact that many of the scenes and characters look nothing at all like their counterparts from the Disney movie.
The inside of Mermaid Lagoon is substantially less abstract and closer to the standard Disney themed adaptation of an animated environment, albeit finished quite well and with TDS's usual surfeit of detailing. There's actually a subtly thoughtful transition from exterior to interior (and from more abstract to less abstract) in the form of a depiction of King Triton that's more a statue than a standard theme-park static figure, but which is situated in a more cartoony space, akin to that of the land's interior areas.
I haven't seen FLE's Mermaid facade (or Belle's village) in person yet -- other than distant glimpses earlier in the month, from other parts of FL -- but from the photos I've seen, the structures and rockwork look to be among the best at WDW, and for that reason alone, are a welcome addition to the MK.
But as I've said elsewhere, the theming of external environments, ride structures, and queues can only take you so far. Part of the reason Cars Land works, beyond the attention to detail and utter fidelity to the Radiator Springs seen in the movie, is the fact that the gorgeous rockwork interacts with and is an organic part of a true E-ticket attraction that is rightfully the star of the DCA expansion. (Had Cars Land only included the modest Mater and Luigi rides and a meet-and-greet, it wouldn't be the subject of nearly as much adulation.)
Likewise, the fantastic centerpiece of TDS, Mysterious Island, is widely acclaimed in large part because it comprises two original, ambitious, and sophisticated attractions -- Journey to the Center of the Earth and 20,000 Leagues Under the Sea -- that would, in and of themselves, be a strong argument for a visit to the park, even sans surrounding rockwork.
Beautifully realized landscapes and environments ought to go hand-in-hand with high-level rides and shows -- and what Disney has done elsewhere in its global empire, even very recently, demonstrates that it is still more than capable of delivering both components: the two should work together almost symbiotically in an ideal theme park. That FLE seems to have delivered the first part while faltering substantially with regard to the second is, in my view, cause for disappointment at missed opportunities and unfulfilled potential.
