The Death Eater's introduction to Hollywood last year was one of my favorite elements of their event. It just helped bring a little more Halloween spirit into the area.
I know for some, Diagon Alley was seen as a "rest/quiet" area from all the action. However, I think all the extra entrainment this year, such as Death Eaters, should help spread out crowds more in a year without a lagoon show and two massive tentpole IPs (which together are potentially the biggest "gets" they could have gotten this year) might make this year one of the busiest yet.
Now for this year, I could see the lagoon area could still be accessible to guests during the event, making that a new "rest/quiet" area for the event.