According to the article, the G1 X has a CMOS sensor that has 6 times the area of the sensor in the G11. It's only 20% smaller than the sensor in Canon's aps-c DSLRs, such as the EOS 7D. For those who dislike an LCD viewfinder, the G1 X has an optical viewfinder.
I think we'll see a version of the G1 with interchangeable lenses later this year.