I read all the scans those last days and I am surprised by how much good this manga is. Firstly, when I read the summary, it didn't convince me. But the scenario based on the assassination with the reflection about the different ways to educate, it was really good and interesting. I'm looking forward to see the end. I saw you were all a bit upset about the recent turn of events. Personally, I don't really care about a happy or bad ending. It depends on the future events and if the author doesn't mess up by one way or another, it'll be fine.
Actually, I don't think it will be a happy ending, as you seem to fear. I think that the last events were a bit too positive, it's odd. The author gave us a glimpse of a possible positive outcome... Yet, the future events are not going to be happy, the intervention of Shiro won't be a waste of time, far from it. The fact I really have the strong impression it's going to end well makes me think it won't be that easy.