No, it's not to late to add him. Spider-Man is part of the Second Avengers, along with Luke Cage, Iron Fist, Wolverine, She-Hulk, and etc. Spider-Man will be perfect for the Avengers 3 movie since they are trying to phase out the main heroes (because contracts are expiring). Besides, his role wont be big since Iron Man, Doctor Strange, Ant-Man, and Black Panther will be the main heroes.

It's Marvel approaching Sony, not the other way around. They also approached Fox and Fox wants nothing to do with it.

Simply put this is a massive win/win for both sides. Marvel can get a TON of hype by putting Spider-Man in the end credits of Avengers 2. Sony in return gets to become part of the MCU, and there is no losing in that at all.

regardless of what critics said finiancially spider man 2 did well and was a major reason sony actually posted profit for the financial quarter it came out in. Thats why they wont sell it. Basically free money no matter how good/bad the movies are.

I mean can you imagine Spiderman getting the tony stark spiderman suit that he had in the comics in an Avengers movie mmmm

lol wut? xD

Well, considering the fact that Spider-Man is a MARVEL character and has nothing to do with DC (other than that time Marvel and DC got together to do the crossover stuff) I would say you should feel pretty ok with it. That big "M" in the upper left corner of every Spidey comic should give it away.

Or the page flipping Marvel films logo at the beginning of every Spider-Man movie for those who don't read the comics.

In the simplest of thoughts, yes. Seeing Spider-man walking and talking with his fellow heroes is a gigantic win. No one is arguing that.

But is THIS CURRENT Spider-man good to go in The Avengers? How exactly do you squeeze Andrew Garfield's loved by the city web-head, into the MCU who has seemingly no trace of him anywhere! Where was he during the New York incident and where will he be during the Ultron kerfuffle?! As we've seen already everything resonates within the MCU. The aftermaths of a Cap, IM, or a Thor movie can be felt by the others. Shield or Stark would have heard by now about Oscorp who's practically run by Satan in the Spider-man cinematic universe.

Meh, aside from Harry Osborne, I don't have much to gripe about for the casting. Granted, I'd have been much happier with Emma Stone if they would have had her play MJ because Emma is completely gorgeous as a red head, and we all knew Gwen would have to die at some point, but she still rocked in the role, so not much to complain about.

I like Andrew Garfield as Spidey. I think he is a lot more jovial, and he pulls of brooding just as well.