Here's a really interesting article from arstechnica which may allay some trepidation about QTX (although it's still not useful to Pro users at all).
As anxious as developers may be for a full-featured, 64-bit successor to the QuickTime 7 engine, Apple itself is sitting on top of one of the largest QuickTime-riddled (and Carbon-addled, to boot) code bases in the industry: Final Cut Studio. Thus far, It remains stuck in 32-bit. To say that Apple is "highly motivated" to extend the capabilities of QuickTime X would be an understatement.
Nevertheless, don't expect Apple to rush forward foolishly. Duplicating the functionality of a continually developed, 18-year-old API will not happen overnight. It will take years, and it will be even longer before every important Mac OS X application is updated to use QTKit exclusively.