As of right now, I'm of the opinion that the plan is two-fold. The first part is to ultimately use a good amount of time to establish the women up from NXT and, at least as of right now, essentially rebrand the Divas Division as an actual women's wrestling division; whether or not it'll last more than a few months is anybody's guess but I think if Vince actually did talk to wrestling fans that he'd find more prefer the women being used in this way instead of cheap and irrelevant filler.
As to the second part of this plan, the time is devoted to this angle, storyline, rebranding, etc. while simultaneously keeping the title on Nikki Bella long enough to break AJ Lee's record of 295 days. Nikki has beaten Paige, albeit with some help from Brie, and there's really nobody else at this point in time to challenge her. If the idea is to break AJ's record, then this is the way to do it without subjecting the new Divas to losses that'll take the wind out of their sails. You'll notice that all sides in this women's faction feud have suffered wins & losses, but neither Charlotte, Becky or Sasha have been the ones to take the losses because it's too soon.
So after the "Divas Revolution" is more firmly established, possibly in the post SummerSlam environment, with the Divas Championship being put more front & center in time for the Night of Champions ppv.