Collecting data but maybe also just taking a break. Since I thought about it, breaks aren't that bad anymore (they are still somewhat... annoying for the reader but whatever).
Just imagine you're a manga-ka, working like 14 hours a day, drawing and drawing and drawing. Of course, you love your job but it's nonetheless exhausting, sitting the whole day, bending.
Even a manga-ka needs rest and they always need the full time until the dead-line, sometimes they even have to hurry to make it in time. Now, imagine you are working 365 days in a year, or maybe with one week holiday. Don't you think you would feel completely exhausted without a single break here and then? I would. =.=
The issue is that Hoshino takes more breaks than most. :P Still, remember that she's been sick and injured in the past, hence the LONG breaks of previous years, and she still continues to draw. She just got back to doing seventeen pages again! We should be happy for what we get.
As for the ideas thing, well, maybe... it's not that she doesn't know the story itself, but she may not have planned the next arc in very much detail and needs some extra time to do that. =)