Crazycanuk
I agree with your concerns over the reduced communications between flt deck and cabin, but I am not so sure that it is CRM that will suffer, or at least not from the definition that I use.
I think that the latest on CRM is yet again explained by Prof Robert Helmreich et al:
http://www.raes-hfg.com/reports/15oct03-RHelmreich.pdf
CRM is primarily error management. Yes, this does require high standards in many wide ranging human behaviors to support the aim, including good communications. We will be required to adapt our methods and standards of communication to mitigate the deficiencies of the flt deck door, but this is just a small part of the safety picture.
I am far more concerned that current focus on flt deck security by regulators and operators will detract from the larger and current threats – CFIT, ALA, LOC, etc, in which the use of CRM will make a difference.