Judging by the pattern of the Monkey family, where Garp, Dragon and Luffy are all D's, plus Gol D Roger and Portgas D Rouge giving birth to Portgas D Ace, it is safe to assume that will of D is hereditary and thus, Vivi inherited Lili's D and most likely also her legacy and will. But I agree that we don't know enough to conclude what exactly it means.
To me, why being that one clan out of 20 kingdoms feels important since it's been brought up fairly early in the story, plus with the addition of info drop on Lili who disappeared and on top of that thwarted some of the plans of then newly formed WG, with her letter having her will and probably guidelines how to bring the current WG down, it seems like Vivi will still play a big part of the story. Other princesses I remember are Rebecca (I expect nothing of her), Shirahoshi (probably will awaken her Poseidon powers when needed in the final war), Pudding (have no idea what Oda plans for her tbh) and arguably Momo is a male version of an arc princess (guess he'll use Plutón somehow?). The focus Vivi got during Reverie arc and flashbacks of that arc bumped up her importance to me, he story seems unfinished, and I am sure she will have a bigger impact on the new order than the rest of the princesses.
But I can be wrong, I believed in Yamato joining after all