The only immediate good I can see out of this is that Marvel can use the Daily Bugle and J. Jonah Jameson (Bring J.K. Simmons back!!!) as part of their Civil War storyline and Ben Urich can now work for the Daily Bugle in the Daredevil series. It's probably too late to bring in Peter Parker for Civil War but perhaps they have a clever idea or two on how to do that. But as much as I think it's cool to finally be able to unite the Spider-Man and Avengers universes into one cohesive Marvel universe I agree that:
A) Spider-Man does not need to be an Avenger
and
B) I'm not that excited for a standalone Spider-Man film at the moment.
Let Spidey sit on the shelf for a while before he wears out his welcome. Slowly seed him into this awesome world building Marvel has been doing. I would have been happy to hear that Spider-Man was back in the fold and that Marvel had plans for him for Phase 4 but this feel a little forced. Honestly, if they were going to squeeze in another film for Phase 3 I would have preferred to have seen a Hulk or Sub-Mariner film. Hopefully my viewpoint on this will change once we get closer to the release date and the hype train begins.
As far as adding members to the Avengers roster - I want to see more of the classic lineup like Ant-Man, Wasp, Black Panther, Ms. Marvel, Hercules, Wonder Man, Black Knight, Mantis, Moondragon, etc. And I sure as heck don't want Spider-Man meaning I'm going to get less of Thor, Captain America and Iron Man.