The thing is you wouldn't notice it unless you stand right underneath it and look up, it looks fine from most angles. This is our first house and we were pretty overwhelmed and didn't know what to look for, this is what we paid the inspector for. Having said that, this won't happen to us again, I can assure you that.
On a seperate note, can I sue this guy for some sort of negligance? It is obvious now to me as you say, and certainly should've been to a pro.
Anyway, maybe 10-15 degrees is too much, it could be less. I'll do the measurement you suggest.
One other piece of information is that in the attic where the chimney begins to extend from the roof, there is evidence of extensive repair, concrete and newer bricks and stuff. I'm (perhaps nieve and falsely optimistic) hoping that some botched repair of some sort is responsible.