It would be nice but only after Qt's licencing issues etc. are fixed. Qt has bright future in mobile world, but developement in desktop side is lacking (at least so have I heard). This would probably fix that and make it even more instresting and complete toolkit. In a long run this is probably the best for both sides.
However it really should happen in transission of KDE and Qt 5. Breaking backward compatibility twice in year or two doesn't sound good. Tt also should be done in next couple of years, planning something which might happen in next five years sounds stupid in a world where technology developes as fast as it does - or at least I think so.
But how should I understand something like this: "Albert also does not agree with the Qt licensing requirements."?
Qt can also be sold for proprietary software. KDE has to hand over copyright to Nokia so then Nokia can give it back as GPL'd code.