This new camera will be only available 6 months from now, so during this time Canon will gauge the reaction of the market, especially the pro-market, to which the 1 series caters to. They are most likely working on a high res camera, but are threading carefully, with the worldwide crisis and all.
It makes sense to merge the 1.3 and the FF sensor pro-camera lines, and Canon themselves have hinted at that more than once, in the past. 18 megapixels is certainly more than enough for PJ, sports, and even lots of landscape/fine art/advertising jobs, so the 1DX will cater for many professional photographers. They are at a point where they could finally manage to marry a FF high res sensor (18 megapixels) and fast frame rates.
What seems to indeed be "missing" is the "super high res" FF sensor, the "true" successor of the 1DS and 5D lines; I think that these two will be also merged, resulting in a camera that combines a "really high megapixel" FF sensor with pro-build quality and specs. To be honest, the 1DS cameras were just too big and heavy, why the incorporated power grip? Maybe Canon will take the best from the 5D/1DS/7D lines and create a new camera, with pro-build quality and specs, but with the size of the 5D or 7D. All they need to do is take the 5D and build it with the 1DS or 7D quality, updating the autofocus, metering, etc. It would be something like the 7D size and build, but with highres FF sensor.
Speaking for myself, I would be happy if they released such a camera; it is much better to lug around a "7D like camera" than the 1DS monster...