I'm expecting the Pre3 to address the shortcomings in my current phone. At the moment I have a 2 year old Sony Ericsson Satio, that I bought new. Hopefully the Pre3 will be better in:
Speed (as in CPU and the OS in general (The satio has a CPU underclocked to 400MHz to save battery and rocks Symbian S60v5)).
Size & Weight (Satio is a bit of a brick)
Number of apps
Calendar & scheduling
I do still like (but not love) my Satio. When it was new it had many features that were great, and even the iPhone didn't have at the same time (cut and paste, better camera, notifications, alert LED, front facing camera). The Camera on it is awesome however, and in my opinion one of the best phone cameras ever made, which I'll miss when I switch to the Pre3.