I'm probably alone here, but based on how RIM has handled the PlayBook ... I am not particularly eager to see them move to QNX.
1. Apps: All of the QNX apps are written for a tablet - which means a 1024x600 resolution. A subset of those will work on a smaller resolution as well - but because most developers have proven themselves lazy, we'll find that the majority of apps will have been developed and tested specifically at one resolution and will look like crap/be impossible to use on a phone's form factor.
2. Ecosystem: criticize it if you must, but RIM has an extensive and powerful ecosystem in place for "legacy" BlackBerry phones. So far, I am not seeing signs that this is improving - the tools they're providing us simply do not approach the same level of system integration that's provided by the smartphone APIs and tools. That is to say: the integration is completely absent under AIR and WebWorks so far.
If they provide a seamless legacy app player experience; and give those legacy apps the same level of integration they have today, then maybe it can work out in the short term. But I begin to have my doubts, based on what has been delivered so far.
A new BlackBerry development resource site.
