My own thoughts about the trackbalk/trackpad - I don't miss them, and I feel they would hold me back now that I've had the BB10 for a year. Again, just my own feelings on this.

When I first bought a Q10, lack of trackpad did not really bother me, as much as it was a bit of inconvenience, since I have been so used to the iPhone.
iPhone's implementation of text manipulation came a long way, and I understand that the recent improvement of BB10 software is quite on par with the iPhone.
But I now believe that trackpad (not a trackball, which was terrible) is a necessity. Or, let's put it this way, the combination of the trackpad and some buttons are definitely more convenient than none. I think people who say that they can get by without a trackpad are mostly Z10 (touch slab) users. For those, you do not necessarily need a trackpad.
For the most efficient use of the keyboard device, including the one thumb operation, the trackpad is a necessity, and even make sense for keyboard models.