The romance aspect, while implied rather straightforwardly with Sora and Kairi (direct and indirect), hasn't been too prominent and it's been more of an underlying build up than anything. Their feelings for one another are there, no use denying context just to be against a ship, but it appears like they are going to make it a slow burn. Which is fine, because it wouldn't interrupt any other dynamics. It can even take a backseat to the actual plot like it always has been. They are going to walk that fine line of "will they or won't they" for a while. They can continue that while focusing on developing Kairi, which is already set to happen based on her role presented in KH3 thus far. She is training to be on the front lines.
I don't see why to get one, we have to cancel the other. She already likes Sora and vice-versa. That's going to be displayed in the game, period.
I think that people are under the impression that they'll become official. The stepping stones are there. But before we freak out, let's see what the next addition to the franchise leans to and see if they actually get together before wondering whether they should have focused cementing Kairi as a character first.
The same with Roxas and Naminé in that, while laced with some small nuance of flirtation and tease (i.e "can't help you there"), still kept a very vague status in terms of their interaction. Naminé feels and cares for those wronged, and what was happening to Roxas was in her perception, unfair. It is probably also a way to ease off her own guilt, as she's the cause for a lot of memory messes that affected others deeply. The least she could offer Roxas was to give him information he needed and a semblance of a choice in his fate. They are farther away than the position Sora and Kairi are in now, and it's understandable. 2.8 credits aside, I feel it's just a way to imply this is the potential end in the future (as in, this is the pair that has been ultimately decided upon), rather than saying it's going to be canon come next game. The only factor that throws it off is Naminé's line of "so we'll be together again!", yet considering their situation can probably be chalked up to that they won't be alone in this. That there's some companionship in being locked within an individual despite having a self. The rest of the dialogue implies it as well. Back then, they seemed to be intent in making it look like Roxas and Naminé ended up being content with their unavoidable situation. Of course, that may not be the case now, you know, with the changes in the series.
Really, Roxas and Naminé are an example of a person of the opposite sex you meet in a bar or a mall, lol. You're lured in with their appearance and personality, that in turn brings forth some coyness in the conversation and synergy, but otherwise are just two people getting to know each other for the first time. With an added dash of "I'm here to help you" and whatnot. I see it more now that I'm older. They can go on with this as a basis in [a] later installment, again though, doubt they'll be canonized any time soon. Let the creative side of the fandom run with fanfics instead.
It's just that there's a lot of concern for something that's not to be worried over in my opinion.
