Thanks for your detailed thesis on the game. XD
I can see the appeal, but as you mentioned it is a what-if scenario and for me, the non-canonicity of it is what always kept me away. There is no story justification as to why they are meeting and fighting (am I mistaken? is there a story? I genuinely do not know).
i would totally be on board if characters would talk to each other and there would be some basic plot that could explain the reasons for their presence in each universe.
I am sure I would have a lot of fun for like 8 hours, but then, it would become super repetitive. I can hardly see a scenario where I would play this game for 50 hours without blinking.
I don't think this sort of games are for me, but I can clearly see the appeal and I am happy that Sora got in it.