I know comic books dont seem to mind squeezing everything into one reality, but I dont see the need to add Spiderman to Avengers, keep the universe's separate, so they dont end up getting to the point where people ask "the aliens were attacking, NY, and where was Spiderman?"
It almost the crossovers that dont happen which are as problematic as the ones that do.
Take for example CSI NY and Without a Trace, WaT crossovers over with CSI, CSI spin-offs Miami which spin-offs off CSI NY, so logically WaT is set in the same NY as CSI NY, and yet it never makes mention of the CSI NY "Cabbie Killer".
You are now saying im being nit picky, and your right, but since there is no reason for Spiderman to show up in the Avengers, why open the movies up to such nit-picks?
That said no reason the Avengers movie reality, cant have an Oscorp building of its own, just in that reality that Norman Osbourne never become the character we know from Spiderman, because Peter Parker doesnt become Spiderman.
All that said, maybe the next reality can form around Spiderman, maybe the Daredevil reboot, can be part of it.