Random Lighting storms would rock! The stamina run bar would suck.(Imagine how much harder it would be to hit people. Running up mountains and jumping like mario!)
Here is my idea- Custom Arrows! You get some ingredients and take it to the blacksmith, and then you can make arrows with special effects. Like bouncy arrows, or ones that make a circle of burn around where they hit, and or actual dynamite arrows that explode in a few seconds with dynamite effect. Something like that would be intresting.