I am pleased with what i've seen. The concept art is hiding a lot of the finer details of the specific lands. Most of the detail we're being shown is in the hub and walkways. But I have some level of confidence that the final result will be high quality. We've already seen models of Super Nintendo World, and the detail is much greater than what is showcased in this artwork. So I wouldn't worry about that aspect of the art.
The art solidified what lands and content we're getting, and i'm pretty satisfied with what was shown. My biggest concern is that there may not be too many rides on opening day (an issue I have with Disney these days when they announce big new lands or parks). Bit hard to tell from the art though.
Nintendo seems likely to contain the three rides that were in the leaked model (Mario Kart, a Yoshi omnimover, and Donkey Kong's Mine Cart coaster). So Nintendo may end up being the most content rich area in the park. Dunno if the alleged Pokemon area contains a ride or not. How to Train Your Dragon is getting at least the dueling coaster (which I will count as a single ride), but there may be additional rides in the previously cut off bottom portion of the art, some additional buildings can be seen down there (they seem large enough to potentially house a dark ride). I'm not sure if Classic Monsters is getting a ride, it really needs one but i'm concerned because I can't see an actual show building in the artwork. I'm sure Fantastic Beasts will get at least one ride, the art for it shows a very sizeable building for it. So it's a safe bet that the park will probably have a minimum of 5 rides based on what we've seen from Nintendo, Fantastic Beasts and HTTYD. There are other buildings that COULD be rides, but it's speculation from there.
