I'm not sure what this is supposed to mean. As far as I can tell, SNK has set the scene for the setting of the game. They've even said it was canon to the mainline story I think.
So it's not that there was something missing, just that what's there isn't big enough? It sounds like you want a bigger, more fleshed out Story mode? If so, is that really something you were expecting from a smaller, spinoff title like this?
Or no, it seems like you just wanted some new kind of gameplay mode that's different, without being sure of exactly what that is?
But, isn't the base gameplay exactly that?
I think a lot of people probably share your sentiment, though, which is a shame. But, that's exactly why fighters are as niche as they are, devs don't meet the expectations of the general public.
Like I said at the very start of this thread, its certainly disingenuous for us to expect to be surprised or given content that wasn't marketed(in that case NRS-esque levels of offerings as I responded to another), but its equally disingenuous to be reprimanded or taken to task for asking a bit more. To be surprised or intrigued by something beyond the usual staple of modes. I gave a couple examples of fighting games that offered content that drew me to spend money on with clear reasoning. In this case, the value proposition doesn't seem befitting. I'm not arguing it isn't the case for other fans(again read my first post).
The game will do ok I'm sure and limp across the expectation line pleasing players looking for a break from whatever other fighter they rotate. Or maybe it will surprise and perform merely on the merits of its fighting mechanics? But as this thread is proving, the ask is putting off quite a number of potential consumers.