Honestly, I disagree with the idea that we didn't get what the trailer promised, because, functionally, the trailer showed barely anything. I'm personally firmly in the camp that Side Order was basically exactly what I wanted from it, and while yes, it could've leaned darker (Look at the one image specifically that clearly draws inspiration from concepts of longterm nuclear warning imagery), but I think a lot of the idea that Side Order "didn't deliver" on the concepts in the trailer is simply that it gave us little and we sat with that for a while.
If I had to pick something from the trailer to point to as something that I wish made the final product? Well, maybe I'm crazy but I swear you can hear an engine revving in the end of the trailer music, while Marina can be heard talking. Show us Marina's motorcycle, dammit! You can't tell us she has one and never show us!