If I had my way everything after Amazing Spider-Man #200 never happened (although I like Black Cat & The Juggernaut stories).  Madame Web? Ugh! That's when poor Spidey went downhill IMHO.

I NEED to have Gwen & Green Goblin dead.  That storyline was a big part of my comic reading youth.

Based on Comic Buyer's Guide, it's looking like we're getting the "cosmic reset."  I just don't know how thorough it will be, but the marriage will likely be gone (dang it) and the secret id presumably restored.  

But pretending they're not doing that...

Honestly, I don't feel Spider-Man is all that "broken."  Some dismal stories being told lately sure, but you fix that by getting a better writer.  Get away from trying to Change Spider-Man's Life FOREVER every few months and get back to just telling Spider-Man stories.  Bring back the supporting cast, introduce new ones and have them do stuff.  Have subplots.  Fight villains.  Find something for Mary Jane to do.  I think there's a lot of untapped mileage in the "off broadway actress" thing.

For the most part, anything I didn't like, I'd just ignore.  No rewinds, no reboots, nothing.  Even if I may not like them, every story has its fans so I'd only mess with the ones that I think needed to be messed with for the long term benefit of the character (or that I felt messed with classic stories that should be left alone).  

But I remember how ticked off I was (and many others were) when Marvel tried to dismiss every Spider-Man story that had some out since I started reading comics as "not happening the real Spider-Man."  While I can understand the desire to put a character "back on the right path," throwing away 20-30 years of story is a little insulting to those who were there reading them.  Starting the whole thing from scratch is a little more palatable since that puts everybody in the same boat.  But picking arbitrary rewind points is inconsiderate.  And almost never necessary.  All you have to do to make a series "accessible" is clear up the threads, clear out the overly complex stuff and just tell stories with a relatively stable status quo. 

That said, the stuff I would "fix" if allowed to:

The secret id thing - use the upcoming Skrull invasion storyline to debunk it in the eyes of the MU (and it would never be mentioned again).  As far as the supporting cast goes, most would go along with the debunking, but maybe one or two would still know the truth.  Heck, Robbie was implied to have known several times along the way anyway.  Jonah in particular I'm not sure about.  Jonah not knowing has led to some classic bits, but I think there's mileage to be tapped with him knowing.

Norman Osborn's resurrection and Sin's Past - single issue involving the use of clones and the Jackal.  Then it goes on the "forbidden topics" list.

The organic webshooters & mystic connections - Mystic connections gotta go.  Either by one last story to get rid of all elements or by simply ignoring it.  (Former would probably be better to close the doors long term.)  Organic webshooters I'm torn on.  I'd prefer to get rid of them as part of the "no more mystical crap" story, but I don't want to be one of those guys that dumps everything that happened to a character after my personal "Golden Age," either.

(Edited to add - Oh, and I'd get him away from the Avengers, too.  Frequent guest star would be fine, but not an "every issue" kind of thing.)

From all the hints I've read from Marvel online, it looks like the mechanical web-shooters are coming back.

Well, I'd start by firing Joe Quesada........

Brendan's idea was very, very good!

Personally, I think the Marvel Universe should be restarted - - go back to the Kree-Skrull War era (updated to modern times) and go from there.