If Apple had announced a new iPhone with a slightly larger screen (3.7" - 4"), notification LED, and aluminum back, I probably would have jumped right in. While I do see the updated internals as a big improvement, it's not enough to guarantee a sale for me. As of now, I'll be waiting until the 11th to see what my next phone will be as I really want to see what Google and Samsung have in store with Ice Cream Sandwich and the rumored Verizon Nexus device.
It almost seems as though this iPhone 4S was Apple's plan B. I find it hard to believe that they couldn't come up with more than just a faster processor and upgraded camera. It's almost as if they had another phone in development but realized that the new design wasn't feasible at this point in time and fell back to what they revealed today. It's hard to believe that case manufacturers would have radically different case designs on their website if Apple hadn't given them some reason to deviate from the current design.
I do agree that the other OS manufacturers out there have breathed a sigh of relief and that the iPhone 4S will not be the huge seller that analysts were predicting before the announcement. It'll definitely still be successful especially due to the fact that Sprint users will now have a chance to pick one up and iOS 5 is a big improvement. If I'm wrong, I'll definitely eat my words but I'm curious to see how this all shakes out.