Sean Kanan was treated very shabbily by General Hospital when they wrote him out. It's one thing to decide you no longer want to write for a certain character, but the way they absolutely trashed his character and then killed him off with little to no "wiggle room" for a return seemed to indicate a mean-spiritedness behind his firing. It wasn't "just business"---it came off as very personal. I mean, they depicted Sonny (the one who murdered AJ) having sex on AJ's grave. Fans of the show at the time were up in arms, but it looked as if the Head Writer and Exec Producer didn't care.
So while I'm glad to see other shows value Sean Kanan's presence and talent, I'm saddened that it looks like Kanan's AJ Quartermaine will likely stay dead on GH despite his value to that show.