Fromt TFA: "Nokias motivation for this move as being mostly driven through the desire for easier cross-platform-development, citing Maemo, Symbian and the desktop as examples."
One thing that sounds incredible wrong to me is the fact that they are saying that Qt was chosen to make "easier cross-platform-development". The applications that were ported directly from desktop to Maemo (Xchat is the first one the comes to my mind) have an incredible bad look in the device. Building an interface for a device that runs in a small screen (4.1 inches) with a small resolution (800x480) that also uses a large pointer (e.g., most of the screen is designed to thumb usage) is not the same as building an interface for normal computer screens and resolutions.
The move is simple political: Nokia controls Qt now, so they will use their own toolkit. It's not based on merits of the toolkit (or problems of the other.) But hey! Why tell people the truth, right?