Disney won't tell us that right now, but it's something that we've recently talked about in the Halloween at DLR Superthread.
The rumor is that the Halloween party will move back to DCA this year, with
more party nights added into the schedule and an earlier kickoff (like earlier than it usually starts). Cast Members who trained for last year's MHP were supposedly told that "big changes" are coming to the party in 2015. It's only a rumor so far, but I have said (since last year) that it makes sense to me in light of the events of the 60th. Working the new fireworks and new nighttime parade into Mickey's Halloween Party seems to make very little sense for a few reasons, and I can't see Disney deciding to scrap their new 60th anniversary-specific entertainment (in
Disneyland) in favor of running something they run every year, which they can simply run again next year (meaning Halloween Screams and the Cavalcade).
Having the party in DCA seems like it would be less disruptive somehow, and they could turn the focus onto World of Color (maybe a Halloween-ified version of it) and whatever else they add in.
But right now, it's all speculation based on rumors.
I think that the holiday season nighttime entertainment will be impacted too.