I am far from an expert, so will not argue. I am pretty sure that Drew can advise on what suspension jacking forces are. A lot of good info around but Wikipedia helps too:
https://en.wikipedia.org/wiki/Suspension_(vehicle)#Jacking_forces
As I stated, long arms will provide you more wheel travel and articulation off-road
with the proper geometry. If you do not care about proper geometry on or off road, your travel will be limited only by your shock length (or limit straps), or heck your brake lines

Example, same length shocks, on a short and long arm, however notice that the travel curve will be impacted. I.e. from Hammerhead's post:
source
http://www.4wd.com/jeep-lift-kits/long-vs-short-arm.aspx
I am not saying that a long or short arm is needed or will benefit everyone, specially on a JK. I myself am debating what to do next suspension wise, and will probably stick to my current setup when doing my tons, as the ride quality and travel has been great for my daily driving and wheeling style.