Well, considering that people are trading their NATO Kosovo medals in for Allied Force GCSs and GSMs, and that Canadians cannot accept the ISAF NATO medal for Afghanistan due to the GCS/GSM SWA, I think it's safe to say that Canada will be issuing either a GCS/GSM or OSM specifically for Op Mobile.
Your logic is off. Canada will only issue its own medal if no other (e.g. UN/NATO) medal is being issued which meets Canada's criteria for recognition and is accepted into the Canadian Honours System. CF personnel cannot accept the ISAF NATO medal because it has not been accepted into the Canadian Honours System. It was not accepted because it would not have recognized all the personnel that Canada was sending into that part of the world for the operations Canada wanted recognized. Therefore, Canada chose to issue the GCS/GSM instead in order to be more inclusive and meet our needs for recognition. If there is a NATO medal issued that will cover Op MOBILE to Canada's satisfaction, then that will be the one used and no GCS/GSM will be issued
It probably doesn't help that the CF is knee-deep in the QDJM and trying to keep up with all those new OSMs. These issues are completely irrelevant to the question.
Best keep an eye on the Orders in Council website. Parliament is back and they'll be passing lots of stuff in the coming weeks. It will likely appear there first before anywhere else. CANFORGEN soon after. Parliament does not pass Orders in Council
http://www.pco-bcp.gc.ca/oic-ddc.asp?lang=eng&page=secretariats