It's a big deal because I'm sure there are Spider-Man fans out there who don't want this to be another Brand New Day/One More Day situation (especially since it has appeared that Slott has been slowly undoing that over the course of his run). Slott has built up a lot of trust and restored Amazing IMO since then (and I'm one who felt the latter Brand New Stories were pretty good).
This is just the start of the arc as well...we don't know how it will play out. That's what everyone has to keep in mind.