Again, if you think this is the be all, end all of what Spencer has in store, I think it's safe to say you'd be mistaken.
Is Boomerang as Peter's roomie going to be a part of the book? Obviously. But is the book going to be primarily about that and the various hi jinks it entails? Highly doubtful. I have to imagine that Spencer has a bit more in store than that.
And personally, I like that this isn't trying to sell us with some earth-shaking revelation right out of the gate, like some hidden secret about Spidey that we've never known up till now. Instead, it's just a very Spidey-esque complication that carries obvious potentials for humor and misunderstanding. To me, it says that Spencer is going to be hitting an appropriate tone with Spidey.
While I can't imagine he - or anyone else, ever - will be on ASM as long as Slott, I expect he'll be on it more than long enough to see Peter through all manner of trials and tribulations.