And I had no problem with him telling further stories. Just saying that Blackest Night was the best point for jumping off if he wanted to do so. War of the Green Lanterns, not so much as he popped a green ring on Sinestro and it was clear he wanted to tell a Sinestro story. He could have left at that point if he wanted to do so but it would have felt as a bit of an unnatural jumping off point compared to Blackest Night. But I'm all game for Johns to tell further stories if he wants to do so or if he wants to end with Wrath of the First Lantern. But there is no indication that he wants to leave yet and he has invested a significant amount of energy in the Green Lantern mythos so there is equably the case that he might actually stay and continue for a bit longer before leaving. And if he were to leave then I hope its on a good story arc...Blackest Night may have been a stronger place to leave story wise, but Johns wanted to tell more Green Lantern stories at that point, and his run was still a wild, chart topping success then too. He's told, what, 3 years of stories since then? If he leaves after this arc he'll have told at least 4 years more of story. I hardly think it's unreasonable that after 4 MORE years he might want to leave. It's not as though he'll have felt he 'missed' his opportunity; he got to tell 4 more years of story.
I'm saying, if I'm writing a series of novels, I'm going to stop when I feel I want to stop. The fact that I didn't stop after the first 3 doesn't make it less likely that I'm going to stop after the 6th one.
And to use the book example, its not 'I write three books, I can't leave on book four so have to wait for book six'. No, I didn't say that, I meant that there should be a natural point for a story to end (like Blackest Night as an example, not saying he should have ended it, just saying there was a good opportunity). So, a story writer can end it at point be that book four, book five, book six or whatever. If it ends abruptly for whatever reason then thats a different case but if you are telling a story then I would hope that it manages to go all the way to completion. I would prefer this to be the case if one is telling long story arcs.