I do not want to give away to much about my game and it isnt really like Diablo 2 more of a tower defense. So to prevent swapping orbs durring a wave I make it so after a wave you have time to craft, swap abilities or items, and some other stuff. If my game was more like Diablo 2 where you can change items any time, I would probably do something similar, you would have to go to a safe hub (A town or village) to swap items or change abilities. Or an alternative is when you swap orbs all your abilities are erased from the action bar (But you still keep the abilities, they are just not bound to the 1, 2, 3, 4 keys).
If I make a Rock Paper Scissor element system I'll probably make it simple and just make enemies take 30% less damage from the element the are resistant to.