Alright! Here are my initial thoughts of Epic Universe. This isn't very structured and definitely not all of my thoughts. I'm sure I'll have tons to say about this park for years to come, but for right now I'll just hammer this out. This whole thing is sort of spoiler-y I guess so feel free to spoiler tag if felt necessary.
Thoughts on Park Areas
The parking lot - this might seem trivial, but this parking lot feels about as big as Hollywood Studios' lot. Picture walking from the back of the DHS parking lot followed by the long walk into the park without a tram. That's what this is. Right now this isn't too big of a deal, but that walk will be absolutely brutal in the summer. It's very odd that they do not have plans for a tram. At the very least, if they don't want to do trams, I think the center walkway should have been covered. It is cool that the entrance music loop also plays on the center walkway.
The main entrance - I like it. It doesn't look like any other theme park entrance. Looks classy, elegant, modern, yet simple. The background music is appropriately classy and, well, epic sounding. There is a very nice reveal of the rest of Celestial Park once you're through the Kronos tower portal.
Celestial Park - I really like this area too. It's like a mix between CityWalk, new Epcot (but better and with a more distinct aesthetic), and Vegas. I also think the Grand Helios hotel is a nice backdrop. I have been to many theme parks, and this area doesn't feel like any other theme park area I have ever been to. It's also pretty massive. You can tell that it was designed with the idea that people would hang out there in between entering lands (while they wait for their time to enter the lands...?). I can't wait to see it at night.
Super Nintendo World - I've been critical of this land but after finally actually seeing a version of it in person, I actually like it. It feels so alive and whimsical. I do worry about two things - being over-crowded as space is limited, and they're really, REALLY going to have to keep up the look of the land, because this type of theming can look bad very quickly in the Florida sun and weather. Luckily, Nintendo cares about their image and quality and will likely push them to keep it looking good.
Dark Universe - unfortunately the weakest land, yet the one I was most looking forward to. Basically feels like a "generic goth" Hogsmeade with a fairly barebones coaster in the back. It's probably a lot better at night, as seeing it on a beautiful sunny day just isn't quite right. Igor and the violinist walking around are a nice touch. Frankenstein Manor should have been framed as a backdrop to the land instead of being kind of off to the side, as Werewolf making up almost the entirety of the back half of the land clashes with the theme of the rest of it and makes it feel open and empty by comparison. Some bad views of backstage and outside of the park near the back that I hope they can address before actual opening with more trees.
Potter - very impressive. No complaints really, but it does kind of just feel like a bigger, more "real world" version of Diagon Alley.
Burke - mostly really good, but has the most views of backstage, bad sightlines, and views outside the park itself than anywhere else in the park. I don't know anything about the IP to comment too deeply. To me it sort of feels like if Volcano Bay were themed to HTTYD, minus something that feels like a centerpiece.
The food - I only tried two things, both in Burke. Spitfyre Grill was delicious, and the mac and cheese spire thing was really good too. I started a thread complaining about UOR's food quality, but if these two things are any indication, Universal really stepped up their game with the food quality for this park. I'm excited to try more.
Thoughts on the attractions I did experience (SEMI-SPOILER-ISH!)
Mario Kart - gonna be honest, I hated this the first time. I gave it another shot though and enjoyed it much more. The pre-show tells you what to do, but it's still disorienting and completely overwhelming on your first run. After knowing what to expect, it is much more enjoyable. Sadly, many guests will only get one shot and/or won't bother with additional attempts. The queue is excellent. The ride's physical sets and scenes are done really well. I wish that the visor graphics were a little less jittery and maybe didn't fill your vision so much.
Yoshi - It's actually really cute and the views of the land are nice. The low capacity and having a height requirement and restraints are going to hurt the perception of this, however.
Mine Cart Madness - Genuinely shocked at how much fun I had on this. It's a bit short and could have used a 3rd segment (perhaps that part being all indoors), but it feels about as long as 7DMT. I've seen a lot of people complain that it is "rough". It's slightly jarring, but to me that adds to it. You're in a janky mine cart riding over broken tracks. If it were perfectly smooth, it would feel more fake. The queue is pretty minimal, but I appreciate that it seems to be air conditioned despite being open-air. Like Yoshi, however, the low capacity and inevitable high waits will not do favors for its perception.
Monsters Unchained - it's easily the most impressive attraction in the park (with Ministry not being ready). However, I have some issues with it. The tone is too cartoony and "theme park-y" when it should have leaned more "HHN". It does indeed feel like an HHN house, though, in the sense that the backstory is convoluted and the ride won't make much sense without knowing it. My other main issue is that it's super chaotic, too much drawing your attention at once. This is a common weaknesses of Universal attraction design - poor pacing and too much chaos resulting in overwhelming you. Forbidden Journey actually is much better about this, as it focuses you on one thing at a time. I know the average person will be dazzled by the technology and won't really care about these things, but for me it does make the attraction fall a little short of modern attraction masterpieces like Rise of the Resistance. All said and done though, it's still a definite "must do".
Werewolf - ehh, it's an okay family coaster with minimal theming. I wish it was outside of the main land instead of going in and around the walkways as the netting detracts from the theming. Overall I think this was a poor choice and detracts from the land rather than adds to it.
Ministry of Magic - the ride isn't ready yet, but you can tour the queue, and it's definitely pretty incredible.
Stardust Racers - I only did the yellow side. It's like 10% less intense than Velocicoaster. I really liked it. Lots of great ejector airtime.
Constellation Carousel - I loved the music, both the calm astral stuff while the ride is loading and the dance-y stuff during the ride. Loved all the steampunk gears on the ceiling too. This is a very "Instagram-able" ride experience and for that alone I think people will dig it.
Overall Thoughts:
First and foremost, does this raise the bar for theme parks? Is it the most immersive theme park ever? The answer to both, and I think most people, even diehard Universal fans are in agreement, is "no". However, there's still a ton of quality to be found here, and it IS absolutely a world-class theme park.
This park forces people to re-think a theme park, and it's obvious you're supposed to enter each land one by one and spend considerable time immersed within it before retreating back to Celestial Park for a break before heading to the next one. However, this is definitely at odds with how theme park enthusiasts and much of the general public tackle theme parks. Some might find it frustrating to continually enter and exit the lands one at a time without any way to take "shortcuts". People need to be encouraged to take their time and chill in each land rather than powering through only the rides.
I do think that each land should have had at least three rides. I of course understand that this is not a new issue for a new theme park and will improve with time.
The two biggest complaints I do have, and these are unfortunately pretty big issues:
1. Sightlines/views of backstage areas. There are, unfortunately, wayyy more than I had hoped for. This may improve in the 2 months before it officially opens, but they're going to have to be planting trees, shrubs, whatever like crazy. The entire conceit of this park is that the portals transport you into completely immersive worlds. However, only SNW and Potter accomplish this, by using their "surround you by tall walls on all sides" trick from Diagon Alley. The back half of Dark Universe and most of Burke needed to be surrounded by a tall berm with a thick line of trees atop, similar to how Galaxy's Edge effectively blocks your view of the rest of the park.
2. The park needs about, I dunno, 200% more trees, and the trees that are there needed to be more mature already. This unquestionably feels like the least amount of shade in any of the 8 Orlando theme parks.
So, yeah. I'm a critical person, but my overall first impression is: mostly positive. Things will only improve from here.