I like that Mada rejected all of them, but at the same time, I hate it. His decision is sort of the "hero's" choice, putting everyone else's enjoyment above his own, and it's not really wrong, because the reasons he listed for rejected each of them made perfect sense, but life is about sometimes abandoning the smartest decisions and making the more emotional ones, for the sake of happiness.
With Angela and Hato, Madarame was definitely right. He wouldn't see Angela enough, and Hato wasn't sure if he even really liked men. Both situations would have blown up before long. But he could have had pretty good odds with either Keiko or Sue. Keiko reminded him of Saki a bit too much, but sometimes that can be better for a person. It might have allowed him to finally get over her, by being with someone similar to her but also very, very different. He could have seen things in Keiko that he loved that Saki doesn't have. And with Sue, they could have done just about everything together, from Comiket to gaming to anime-watching and critiquing to, quite possibly, hentai-viewing. They might have been the perfect match.
To be fair, a relationship with Keiko or Sue might also go very badly, but that's life. There is no such thing as a relationship that couldn't crash and burn. Madarame should have taken a chance and chosen one of them, if just to have the life experience. I'm not questioning Shimoku's decision or story-telling, I can see what he's doing and why he's doing it, and I do like it, but I can't get over the thought of Madarame actually getting to second-base with a girl and getting some boob. I really, really do not want him to be a 30-year-old virgin that has done absolutely nothing with another person. Life is so much better when you have some experiences. And Mada x Sue would have been so cute!