Well, the G2 will give 65 lumens for 60 minutes. It may start out a bit higher than that, and it may end up a bit lower than that at the end of the 60 minutes. The Fenix will be 180 lumens at the emitter, which should be around 130-140 lumens out the front, for 2.4 hours on 2-AA, while the G2 is on 2xCR123's. Going from 65 lumens (avg. out the front lumens for 60 minutes) to 130-140 is double the light, and would be a noticeable difference, I wouldn't call it "not much of a difference".
I happen to have a G2, and a P3D Rebel (closest thing I have to the L2D) and while the Fenix may put out more total light, the G2 P60 incan does appear to out throw it. On my LUX meter the Fenix was around 2,000LUX and the G2 around 5,000LUX! My P3D Rebel has a larger hot spot and more spill, so it depends on what kind of beam you're looking for. Even the Malkoff M60 Q2 was a little behind the P60 incan for throw on the LUX meter. The Malkoff was reading in the 4,000's.