Captain Canuck
The poster formerly known as captaincanuck65
I don't think it's that. It has a rotating team of writers so it's not like it's Bendis writing 15 books a month, stretching himself thin and having it show in his work. But the writers could definitely be better.
However, the main focus of the editors is getting the book out on time and not on quality.
Has anyone said how long they plan on doing it like this - having this be (basically) the only Spider-Man book and having it come out weekly?
Nope, they haven't.
I'm pretty sure the plan is to do it for as long as it works. They plan the story arcs out a year in advance, so if and when they do decide to stop they'll know that far ahead of time. But as far as I can tell from reading the letters columns and interviews, this is the new status quo indefinitely.