Too many loose ends. What about his Dad? He has to eventually show up out of *nowhere*, when everyone least expects it, to save the day. The whole king thing has been hyped up, as well as that homonlfasdfsdklous(spl?) thing that is not fully powered. So we are going to have to see the king, somehow. The key to get there will be made one way or another. I would expect the King Arc may be the last, but after the king is saved he may send Ichigo on a mission to save someone, maybe in Hell or something for the Hell Arc. That should end it. If they really get creative, it turns out the king is a bad guy (or an imposter) and Ichigo must go back to defeat him. I can't see things going further than that.