That's what I don't get about ChojixIno. They never had any development as an actual romantic pairing. Nor was it ever implied that they had romantic feelings for each other.
About Choji and Ino: Waaaay back in part 1, there was some discussion about Choji's weight and never getting girls. And Shikamaru cheered him up by saying something like you're a nice guy, and the right girl will see through it or love you for it, or something like that. It was around the same time as Shika's interactions with Temari.
So later in the manga, a couple of time, Ino says how nice Choji looks when he's skinny. But then she also understands that his power comes from his heft, so basically, she's seeing him completely.
Anyway, the dots are there if you want to connect them. And it's not hard to see why people would pair them anyway — they resolve each other's character issues by seeing each other as they truly are, which then helps them to become better individuals. So it's the classic archetype of the character only being validated by some component of their love interest.
In going with Sai/Ino, Sai gets nothing and Ino looks like a shallow girl who went for the Sasuke look alike who once called her beautiful when the audience knows he meant the opposite. That resolution does not elevate her character. In fact, it goes backwards.
And Choji's pairing makes it feel like Kishimoto was just pulling names out of a hat!
He has seen the truth 
