Hi,
The G4 looks better than the DL 752, though there are still a few minor issues with softness/sharpening.
As to your points,
1. I almost always use support (tripod/monopod) when shooting past 300mm effective, and if I'm up in the 500mm+ plus range, then it's a must to combat shake, as I don't like bumping up the ISO. Plus, it can get tiring always having to support all that weight if you're only shooting hand held with a longer lens
2. Shooting RAW is most beneficial for correcting exposure and color problems; it doesn't really help that much when it comes to sharpening, and of course can do nothing about heat haze.
3. Not sure what that means, but if you are trying to avoid oversharpening, I agree - the only place I see it badly is the leading edge of the wings in the G4 shot. The DL 752 has evidence of oversharpening - I think this is what you must mean by halos... adding more sharpening to the DL is not going to help. I was trying to imply that you had already added too much to try and compensate for a soft shot, and it wasn't really working too well. If I've ms-interpreted, let me know.