Responses
Just the fact that his sempai was surprised that he could be recognized "with different hair" made it obvious to me that he'd seen sensei instead and that that would be the default pairing.
I read a lot, manga and novel, so I notice the author's intentions more than I might otherwise.
I think many would love for a Hikari x Senpai ending but, I was rooting for Sensei since the beginning and I was still disappointed with the ending. Senpai has a lot of issues with his girlfriend and I don't think that will result to a good romantic relationship with Hikari. Even though Sensei said those things to Hikari, the way the mangaka draw Sensei's expressions shows that Sensei was also struggling on his own love. It seems like he was confused in the middle because falling 100% in love with Hikari meant that he has to let go of his current self, which he has known who he was for years after he broke up with Shuu. He was clearly pushing Hikari away because he doesn't want to lose his current self and ending up forgetting about Shuu. That's the reason for the phone call and everything in between. The mangaka did not portray this directly through monologues but Sensei's struggle was obvious to me and that Sensei himself was in denial that he loves Hikari. Hikari, on the other hand, did not just fall in love with Sensei because of sex. I would like to remind everyone that Hikari thought that Sensei was the only one who can accept him as Hikari, his true self. He realized that despite what Sensei said, Sensei still cared a lot for him and he chose to believe Sensei's actions rather than what was said. Also, in my opinion, Senpai was a figure of puppy love for Hikari, an infatuation. It really was not meant to be for them. Hikari's image about Senpai was like admiring an idol or an ideal guy. Facing a person who cared for his true self, I kind of predicted that Hikari will eventually fall for Sensei.
Just my two cents on this manga.