He's not out of ideas, seeing how he has a lot of it written in advance. He may throw in a few changes come print time but he is way ahead of the manga if not the whole thing done. He doesnt do it from week to week just making up stuff I assure you.
Plus Kishi has to put things in there that foreshadow things to come, or have flashbacks of important parts.
It would be nice for a 50 page manga or somethign though =]