My gripe list:
hardware:
-- No improved camera
-- No camera flash
-- No external LED indicator for new mail/messages
-- No videoconferencing (front camera)
-- No LED backlit or OLED screen
-- No larger and/or higher-resolution screen
-- No user-replaceable battery
-- No 32 GB option (and $100 premium for an additional 8 GB seems a bit much considering I can find an 8 GB USB 2.0 flash stick for under $20-$30 now).
-- No mini flash memory expansion slot
software/firmware:
-- No local storage for files
-- No video recording
-- No universally-available horizontal keyboard
-- No cut and paste
-- No picture MMS
-- No way to select and email more than 1 photo at a time
-- No basic editing controls for photos (crop, rotate, etc.)
-- No way to specify the downscaling (or to stop it altogether) of photos synced from your computer
-- No way to use .Mac account aliases for sending (it always uses the master account address)
-- No ability to download, save, and sync files from the web
-- No real-time chat (iChat)
-- No Bluetooth support for external devices other than earsets
-- No notes syncing
-- No categories for iCal events
-- No master on/off switch for all alarms (clocks)
-- No preference for adjusting touch sensitivity (I'd like a slight longer tap delay since I'm constantly firing off links accidentally in Safari when I'm really trying to tap and drag)
Now of course some of the software items may show up at some point, I just haven't heard of them yet. Despite some disappointments, I'll still be getting one on July 11. The 3G, GPS, and Exchange support alone are worth it.