I dunno, maybe we disagree on what WA2 was trying to convey... I felt more that Haruki certainly was pretty messed up in Introductory Chapter, and certainly he decides to rectify things during Closing Chapter. But taking Kazusa route, normal or true end, felt a lot like a
Heel-Face-Turn in terms of character. Sure he goes to save Kazusa and be with her, but he essentially destroyed everything he'd built up in the two year gap in order to do so... I kinda skimmed the route myself, but I guess you're in one of two camps when it comes to WA2:
1. You want the three of them to at least reconcile
2. You want Kazusa to be the one who wins in the end
Reading the side material myself, it'd seem to me Haruki (when he's thinking straight) cares a lot about keeping promises and treasuring friendships. Should probably note that the Setsuna true route is the one whose credits roll is treated far better than Kazusa's, and Kasuza's matches pretty much all the other characters' credits rolls. If anything, Kazusa's route seems more like the omake scenario. Setsuna true route, even though it's labeled "Setsuna", was still about Kazusa and getting her to grow as a character nonetheless.
I guess if you care a lot about the love triangle aspect more than what the three initially wanted to be, then camp #2 is for you. I'd fall into camp #1 myself.
Besides, I think it's better the anime broadcast itself goes with Setsuna true end. Other characters could get fleshed out as OVA extras, much like what happened with CLANNAD and After Story.
Addendum: I'm not saying that Kazusa's route was a bad idea at all. On the contrary, it's essentially telling what would happen, and yes the dramatic impact is certainly there. But if there were a Kazusa route that at least matched the same kind of ending Setsuna's route got, it'd have to be one that forks from where Haruki was given the option to go to the concert (troll option, you can never pick this). Fandisc, anyone?
Addendum 2: Reading the side-story, The Idol Who Forgot How To Sing / 歌を忘れた偶像(アイドル), will also give some insight into Haruki's character.