>>528495737
I think its mostly because its on a Nintendo handheld. BBS was on PSP with more or less the same buttons & graphics as the PS2 games. It also had secret movie hype going in and got to be dubbed KH0.
DDD also feels like CoM, Days & Coded because Sora was playable in all of those, Riku in two and heavily involved in the latter's story. At least SE are consistent with the important side games having new worlds. "dreams" as a theme could've easily been a third KH1 rehash to go with memories and data.