We think: yes. There are several reasons to believe just that, among the least important of which is the fact that MS was among the group of companies who originally submitted the standards effort to OASIS. However, there are other things that make us believe that CMIS may be in for a treat by MS, particularly that MS folks have started to prove the point of CMIS by actively publishing an example about CMIS-based MOSS integration on MSDN.
The article explains how to integrate a CMIS-enabled repository using an external repository definition in MOSS. The nice part of this approach is that documents from an external repository may become part of MOSS workflows, undergo changes, and best of all, can be made part of MOSS libraries without the necessity to be stored in MOSS. The last feature allows such documents to become part of task lists etc., without the need for web parts. It is noteworthy, though, that a protocol handler is still required to make the contents of the external repository searchable, and that the usual caveats apply in the area of mis-matching security models and settings.
It seems easy enough to walk down this road for content integration purposes, and MS makes a point to mention that the use of CMIS provides for a platform independent implementation. However, the authors point out that the implementation is not complete. Also, while this explains that, using CMIS, it would be possible to address, say, SAPERION running on AIX, there is still no mention (which we were able to find) of exposing MOSS repositories using CMIS. We think that this would be a logical next step, or would it?