G1X with an APS-C sensor? Hmmm.... Nice but could be too big to be one of the "G" series. If compact enough like G1X, then count me in. This can be a very good backup/fun camera if the on-sensor dual AF can be copied from 70D. 10 to 15MP should be more than enough. I like a 17/18-135 F3.5-5.6 lens though.
On the other hand, why not the eos-M with a viewfinder and a built-in flash instead? Both should be almost the same size. G1X with APS-C sensor doesn't make sense really unless they can make the lens smaller and retractable just like the G series.
G1X... compact? I think our definitions must differ, I find it pretty bulky.
Likewise, I think that the other G-series are now too big for the level of performance that they offer; I never did like my G12. Hopefully a G1X successor will offer an EVF instead of the crappy tunnel viewfinder of the rest of the G-series.
Maybe they'll follow Sony's example with the RX10 and move to a larger sensor in the SX series, as I don't think that increasing the focal length of the lens is really achieving much.
The G series is still quite compact compared to some DSLRs... For an APS-C sensor (as rumored) if they can maintain the size of the present G1X, this is still one of the smallest even among mirrorless aps-c.