The tech is spectacular. Hands down. It's super impressive. Arms have cool lighting and in several scenes are used really well.
Despite what others have said, they do roll out new tricks as it progresses: stargate pyro, lasers, arm pyro, perimeter pyro canons, spaceship earth lights.
I don't know quite what it is, but there's no denying it's a technically-impressive something
To paraphrase Dr. Ian Malcom from Jurassic Park: "Yeah, but your Imagineers were so preoccupied with whether or not they could, they didn't stop to think if they should."
It's absolutely technically impressive, but it reminds me of something that would be more appropriate for for a music festival like EDC or for a mega stadium concert tour. Just because something is technologically amazing does not make it right for this park.
Part of the amazing aspect of Illuminations was that it all happened on the lagoon and most of the hardware was invisible during the day, so it just seemed to "come alive" at night. Same with the original F! at Disneyland. Placing four giant tacos to serve as jumbotrons is the least creative decision they could have made for how to present filmed visuals.