Most of the negative stuff i've been reading is from people who read too many rumour sites and were expecting an iPhone 5 with a bigger, higher-resolution screen, thinner form factor and handjob ringtone buzzer.
If you look at their last three releases, they went iPhone 3G, 3GS, 4G. The 4GS is totally what i expected. The fact that it's combined GSM and CDMA is pretty awesome (and hugely profitable for Apple) and the dual-core processor and new camera look pretty sweet.
Siri looks brilliant, and really looks like a game-changer. I'm sure RIM and Google will be ripping it off in 3... 2... 1...
I wish it would have worked on the iPhone 4, but i guess that's how they sell new hardware, huh?
I'll be happy with my iPhone 4 with iOS 5 for another year or two.