After playing a portion of dwayne's available route i think i can pinpoint why i find dwayne so off putting.
Dwayne is haphazardly implemented at the start of the game, the player's introduction to him is having this creep feel you up, compliment your body, immediately pushes you to help him move stuff out of his office/classroom, dumps about his dead dad, then has the audacity to ask you out. If that isn't bussy repellent, idk what is. If you do accept his offer the route pretty much have this guy speed runs his way into a relationship with the player. If we compare this to Richard slam dunking the player into a relationship at the end of day 7(iirc) there is one stark difference. It's established that Richard and the player has know each other for some time before the events of ExA so there is a level of familiarity with each other before they start getting serious. Dwayne on the other hand is just some guy from the school. To me it feels off that he wants a steady relationship with the player so quickly. Another thing is how disconnected he is from the rest of the cast. You date one of the main 5, the other 4 will take a minor role in said route but you'll still be able to interact with them. Not dating richard, you still see him at the shelter along with Maria. They will also come to see your matches. But Dwayne, the moment you tell him you're not interested, he disappears outside of a very minor role in Harold's route during the book signing event. No encountering him at random places in game, he doesn't exist. I'm guessing rewriting portions of the early parts of the game to include him in someway when not dating him would be too much work ?
I am also not sure on if Dwayne is supposed to be neuro divergent or just a quirky airhead. The color synthesia or what ever it is kind of implies he is neuro divergent but then there are other little instances where the argument of airhead might be valid as well. Subtlety has never been ExA's strong point and I rather them outright tell us.
I've dunked on Dwayne's design to hell and back. But when CBG has made sexy gorilla men, Dwayne is just completely underwhelming Case in point
TL;DR: Dwayne is a poorly implemented extra that no one asked for and it really shows.