Well in COD4, all the snipers apart from the M21 and Druganov (I THINK!!!!!) are one shot kills to the groin (under your ribs), while on CoD WaW, all of them are one shot kills to the groin, as you can see in the video someone posted earlier.

So the WaW snipers are stronger, and pretty much allways a one shot kill, so in that sence, they don't need more skill, but then again, who uses the M21 or Druganov, everyone uses the M40A3 or 50. cal, and the really good people use the Remmigton...

But then, the M40A3 has pretty much no recoil compared to the WaW snipers, apart from Springfield and PTRS... So basically, COD4 = mostly one shot kill, low recoil. COD5 (WaW) = always one shot kill, low-medium recoil

I think that Infinity Ward was realistic, not making the 50. cal have no recoil and one shot kill on Jugg... but that Treyarch, failied and made it so unrealistic... all one shot kills, and having low-medium recoil, when back then it would probably shoot up a couple of inches (the gun raise off the ground)