Gotta go with Sins Past
The custodians of a flagship book literally reached back in time, shit all over a seminal story and trashed a beloved characters rep, produced a half assed follow up, then dropped it. Leaving us wondering why? Know it's not the worse, but it's my Han shot first I hadn't read a SM book in ages, grabbed that one off the rack when snowed at Denver airport ... Opened it to Normans O face. That's literally the first panel I'd seen in 10 years....
Second would be all that spider baby crap that lead up to ditching the marriage ...Peter and MJ together was kind of something that brightened even the really bad stories ... Nothing they've come up with sense made that appear to be a good idea
Third is clone saga of maximum carnage .. I give them some credit - Ben and some of the pieces were good, just overall it dragged on and down