1: MMS (it's a very useful feature & in my case I get them from my girlfriend, so I'd expect it to have it)

2: Portrait (there'll be some portrait coming soon, but not enough for me & the day-to-day end-user)

3: It lacks phone functionalities, which normal users look for now a days. So Nokia failed at that aspect, it's just a better N810

4: No Navigator and stand-alone number keys which makes the physical full QWERTY keyboard less usable.

5: Reduced screen size comparing with N810 and the battery is a lot bit too small for this kind device.

6: Lack of Capacitive screen + with multitouch (it's a step back in technology, at least to the normal users)

Over-all, the device is a powerful machine, but it just doesn't bring it to todays expectations. The freedom + power isn't enough to sell to those people who expect more phone-power (yes, I know, phone second, etc, etc....still disappointing for most people looking for an all-in-one device)
I'd only recommend it to techies.