The ski-jump on the first generation was a finger rest to prevent accidental (negligent) discharges. Apparently, some .mil or .gov types (german, i would assume) cried about the ski-jump giving them a blister, so they redesigned it. Personally, I think the discomfort stems from improper grip.
I have a 1st gen w/ skijump, and I love it, and I prefer the look/feel of the trigger guard as well as the serrations on the slide. However, the proprietary rail sucks balls... im thinking about throwing my frame into a CNC and making it a picatinny down there.
The slide is scalloped on the 9mm due to the mass of the slide being too much for the weaker 9mm to completely cycle. The scallops remove enough mass on the slide to allow the 9mm to cycle the gun.
If your getting bit and fail to RTB, then try different ammo as suggested, or stop LIMPWRISTING it!!!!