DOA 6 was a major step down from 5 content wise, not only we didn't get guest characters or all DOA5LR DLC characters (except Mai for obvious reasons) as feature standard to replace it, they still made Nyotengu as a pre-launch DLC and Rachel and Momiji as later DLCs.
The Story mode is a joke, barely anything is connected, its about random stuff that happens while there's the main tournament, but it doesn't go anywhere, the only thing that happens is just the confirmation of fan speculation that Honoka is actually Raidou's daughter (and therefore Ayane and Kasumi's sister).