I agree, at best it will probably be the same sensor as the G1X, which is essentially an APS-C sensor cut down to an unappealing aspect ratio.
What's so magical about the 3:2 aspect ratio? Most medium and large format film stock is squarer than 135. If this aspect ratio helps make the whole system more compact, then I'm all for it. If it was simply to appeal to previous Powershot G-series owners, then I don't see the need.
The Fujis are still more appealing: cool design and nice, standard APS-C sized and proportioned sensor. I just don't want to invest in a non-compatible lens mount.
Everyone seems to be heaping praise upon the Fujis, but I think that they're both (I'm excluding the X10) too niche for Canon. The X100 is an enthusiast's second camera for use in certain circumstances, primarily when enjoying the camera experience is as important as getting the shot. The X Pro1 is Fuji gambling that there is enough of a market for a budget version of the Leica M9. This is not the market that I think Canon want to target; they need to find a camera that can be marketed to casul users in place of the small sensor point and shoots that will soon be totally obsoleted by camera 'phones. A secondary group is (primarily EOS) DSLR owners wanting an additional, smaller 'carry everywhere' camera. The Fuji X100 is too inflexible for both of these groups' needs; the X Pro 1 is too expensive and intimidating for the former group and too large for the latter group (and a bit too expensive for most). As for their 'retro' design, if retro means more physical controls then that's great (but this does have implications for body size); if it's simply copying fifty year old styling cues, Canon should leave this to German car manufacturers.
I just don't want to invest in a non-compatible lens mount.
I didn't want to take the previous quote you out of context, but I think that the last sentence is very important. No one is keen to spend money on a new lens system, particularly when there is so much uncertainty about which will last. If you had to re-purchase all your DSLR kit, which lens mount would you be confident investing in: EF, F, A, K, 4/3rds? There are two mounts in that list that I would have very high confidence in, with the third not far behind; of the other two, I would be very wary of one and wouldn't touch the other with a barge pole. I don't need to say which is which, as I'm sure that most people already know!
So, out of the following mounts, pick the winners: micro-4/3rds, E, Q, 1, XF, [Canon(?)] ? Not so easy and the potential for an expensive mistake.