I think we confuse ethics and fair chase. Ethically, it doesn't matter how far people shoot because I am not going to judge their capabilities unless I am around them alot. I think there is a fair chase argument when it comes long range tho, the ability of an animal to detect the shooter (by sight, smell or hearing), etc.
Now, as a thought experiment, what do I think would be effective methods to limit range and basically maintain current technology:
1. Rifle weight - I think we could limit the max rifle weight (ID already does it, something like 16 lbs?). Theoretically, you could push this really low, say 7-8 lbs scoped max rifle weight. It's just plain harder to shoot a light rifle than a heavy one, everything else being equal.
2. Caliber Maximums - You would never convince agencies to do this, but you could limit all big game hunting to a max caliber of .244 (Until Avery comes out with the 6UM Ultra in a 50 BMG case and a 180 grain 6mm bullet with a 1-2 Twist...)
Outside of those 2 I don't really know how you would mandate range with current tech other than some feel good idiotic legislation that just pisses everyone off.
I am all for increasing weapon restricted seasons (black powder muzzy, primitive archery, etc.). I'm excited to see what happens in UT with the units that went this way.