As has been mentioned here, the short magnum will give you a slight boost in velocity. You mentioned that you'd be hunting where there's lots of open areas. The added velocity will give you a small edge.

Ammo variety isn't that good right now but should get better with the upcoming production of cartridges from Federal. Ammo availability is iffy where I am, other locales report better luck.

Recoil is not bad at all, guns tend to run a little lighter. If you load your own, or ammo price and availability is good where you are, there's really no reason not to go for the WSM.