CCXML has been a "de facto" standard for some time now and implementations from different industry vendors has been available for some years.
In the last partner conference, i was able to talk with Mark Kowal, ININ Product Manager for Speech applications and we talked a bit about this.
He told me that, for now, they haven't seen enough demand from customers nor partners to made them think about adding native CCXML support to the CIC platform.
After all, CCXML is just a sort of CTI (XML enabled). Advantages are a pretty straightforward integration with VoiceXML based applications and both them complementing each other quite well.