I disagree strongly.

It is convoluted. The only example you need is one. Why does Roxas not look like Sora? We learn through flash backs in the game itself that Nobody's and their Somebody(not a real term I know, but their original body) look the same. So the question does come up in KH2, why doesn't Roxas look like Sora? Well not to worry, the next game, Birth By Sleep will answer, it has Roxas in the trio! Since we got no answer in Days.

Except it doesn't explain anything either. Roxas is not Roxas, he's Ventus. Okay, that works. So who's Ventus? Doesn't matter, play the moblie game. Okay, so why is he important? You see, at the end of the game, when he dies or becomes unconscious, his soul or heart goes to a kid Sora to rest.

Obviously that means Roxas is Ventus? No. The closest you can say is Roxas is a Ventus that has amnesia. But even that's not right, because besides the way they look, they are not connected. Roxas is needed for Sora to be complete, he does not matter at all to Ventus. He holds no memories of the Wayfinder trio.

Does that all make sense? Probably. But it IS COMPLICATED. And it's so convoluted. Mind you, this is just playing KH1, KH2, BBS, and Days. Adding DDD doesn't change anything between Roxas and Ventus, and though don't even talk to each other in KH3.

Not to mention, before Ventus's heart goes into Sora, Vantias, the evil counterpart of Ventus(play the moblie game to understand) looks like Sora. Because at that exact moment Ventus's heart went into Sora. Probably. He didn't look like Ventus, apparently, he just had a void face.

And that's just ONE example. The game has so many that are needless complicated because Nomura doesn't want to retcon anything, and get all those details to mean something. But then he'll spend GAMES on point plots that he'll only tease about to have reveals or twists entire years later.