I think that Civil War : The Return will turn out to be a lot more important than people realise in the long run.
One of the most fascinating things about Civil War and its surrounding books is the sheer number of big, sweeping changes that have been made to characters along the way. Big, honking great changes that you can't really see them managing to find a plausible way round. Mainly, I'm thinking about the Spiderman secret identity reveal here. Coming out, on national live television, and all the reactions shown around the Marvel U have certainly made that reveal pretty much untakebackable. Especially as Joey Q has said that Wanda and/or Doctor Strange wouldn't use magic to alter it.
And yet, Spiderman as a core concept, needs the mask, the secret identity, the bad luck. To be Spiderman, you have to have the feeling that even when he wins, Peter loses. He stopped the villian, but stood up his girlfriend. He saved the city, but the police all think he was trying to steal something. The core of Spiderman is With great power,... and he works best when struggling against great odds, hated and feared but still perserving because it's the right thing to do.
He needs the secret identity. He needs the Daily Bugle and JJJ. He needs to get back to those kind of stories. No coincidence that the movies have portrayed him that way. This is iconic Spiderman, and Marvel would be cutting their own throat if they didn't reset him to that somehow. It's taken them 5 years to get Matt Murdock back as a lawyer, but that reset button has been well and truly pressed.
Which brings us to Civil War : The Return, a hastily written and editorally conceived tie-in, which appears to have very little connection to the main storyline. A Captain Marvel from the past is somehow brought forward in time before he died, and is made prison warden. At some point, he'll go back to when he came from, fight Nitro, get exposed to those chemicals and eventually die of cancer.
Only, what if he never goes back?
Nitro steals the chemicals. Nitro gets exposed and eventually dies. Nitro does not cause the Stamford disaster that started the whole Civil War mess off.
Time could well be fractured, break up and eventually reform. Sort of a mini-crisis. Anything in Marvel history since then could be changed as and how the editors/writers see fit. And in the meantime, knowing they have a safety hatch, they can do whatever they want, and make whatever changes they like, knowing if the fans don't like it, they can change it back, keeping all the stuff that worked, dumping everything else.
So, given Joey Q's known dislike of Peter Parker and Mary Jane's marriage, I expect that to go. In fact, given the whole possiblity of resetting stuff, I expect MJ to be the one killed by the sniper in the next Amazing. And Captain America to die in Civil War too.
Of course, I could be completely wrong. I could well have egg on my face by Friday. But I'm going to be completely fascinated while reading Civil War on Thursday to see if I'm right.