My wishlist:

1. Make the USB port accessible when the kickstand is closed. Or perhaps a docking station (kickstand closed, but something with a low profile for audio, usb, and charging instead of the connector nest on the right side of the device.

2. Move the ambient light sensor where I won't keep covering it up with my left thumb.

3. Do a microSD card instead of the 2Gb internal, perhaps like the n800 where it would be in the battery compartment. Or maybe two external microSDs?
4. Some hw/sw bugs - BT killing Wifi, the GPS having trouble locking (until you remove /var/lib/gps/nvd_data). Tablet as wifi AP (master mode, sharing usb network internet link).

Other miscellaneous:
Video output. Higher rez camera. External/attachable hi-capacity battery. EVDO option (sprint/verizon 3G). Maybe GSM 3G option (T-Mobile/AT&T). ESATA. Digital Audio I/O (or at least beyond microphone/headphone)