Ok first off, I loved it. The constant Can't Spit It Out got a bit much at times, but the character development and story progression were fantastic and I'm a sucker for happy sappy endings. BUT poor Itsuki got Put on a Bus in the worst way possible. It's like the author went "well crap, I can't figure out how to resolve this, I'll just ship her off to America." By about chapter 13 I started to think, "where the hell is Itsuki already." The video at the end didn't really resolve anything up for me. "Hi, I'm happy now." Bleh. Izumi sort of met the same fate. Seto lets her know that he's in love with Iori and she just sorta stops showing up. (Which is weird considering she's already confessed how much she loves him and how she's not going to give up on him, no matter what.) So, overall I really liked it, but I feel like poor Itsuki and Izumi got ditched just to wrap up the ending, which is really too bad considering how much effort went into making them unique and endearing characters to start with.
Agreed that it sucked we never saw Itsuki again. I suppose in the author's defense, it did lend a bit of realism to situation: that sort of thing happens. And it made it easier to focus on the other girls as they drifted on through Seto's life. But yeah, it bugged me too.
Metareason: Itsuki got Put on a Bus because otherwise I"s would have become a non-scifi remake of Video Girl Ai. Iori and Itsuki's situations at that point were becoming dangerously close to that of Moemi and Ai, their Video Girl Ai counterparts. It's similar to how Rumiko Takahashi made sure that the official couples in all of her post-Urusei Yatsura works would have Belligerent Sexual Tension in order to avoid what happened in Urusei Yatsura, when she was forced by her superiors and the fans to make Ataru and Lum into the Official Couple, instead of having it be Ataru and Shinobu as she originally intended. As for Izumi and Aiko, they were never seriously in the running (probably why Aiko was never featured in either anime version), Itsuki was always the most dangerous competitor to Iori.
So we all know the reason why Seto loves Iori seeing how he's the main character and all, but we never find out exactly why Iori loves Seto. She says herself while telling Seto about Izai that her love for Seto goes back 3 years (Which is most likely around the same time that the story starts at or even a bit before that). I kinda wish that Katsura elaborated a bit more on her feelings and gave a bit of a flashback showing how and why she started to like him...
Why in the world would Teratani initially blow Yuka off? Is this not the man who has from day one established himself as the man with the plan to pick up girls? And when offers herself to him, he says no? What in the world is this? Considering how often Teratani is rejected, you'd think he wouldn't try to be so picky.