I'm probably in the minority here, and it's too early to tell, but I honestly really hope they don't do the 80s vibe in the park exterior again.
One of the reasons I go to Halloween events for for a dark/scary/oppressive atmosphere. This is something that Universal Orlando has historically done much better than Universal Hollywood, but has gotten away from in the past three years or so. Knott's Scary Farm also does a good job of this. The party atmosphere doesn't really scream Halloween for me, and it often detracts from my own personal experience. I like Carpenter Brut/The Weeknd/80s synthpop as much as anyone, but when it's the whole music loop in the park, it really doesn't land for me. I'm not saying everything has to be metal or dark orchestral, but I miss it when it isn't there.
(Usual disclaimer that I'm aware that the event exists to make money and not to make me happy and I'm not the core audience.)