I think part of the reason he's not seen as much is if Lena rejects him, then he's not gonna be shoved in the player's face. Just like Arthur in GGGB. If Lena's not on his route, then the last time she will have seen him is the end of chapter 9. Right now, I think he's only an antagonist to Lena. Not so much Ian, at least not yet since the only way he can get on Seymour's bad side is if he calls him out after Lena rejected being his whore. To me, Seymour is the secondary antagonist. The main antagonist is Axel. The source of Lena's trauma, Ian's de facto archnemesis, possibly a traitor to Ivy, and definitely a huge threat to Wade and Cindy's relationship. The game does well to show just how troublesome Axel is to everyone around him.