I chose i/l because I don't want to get hit so MR would be the one I pick to reduce. Also you should kill faster when you are at higher level meaning less chance to get hit. I could be wrong post BB though.
A second choice will probably be BB since it annoys players around you due to its animation esp. bossing in a party.
A second choice will probably be BB since it annoys players around you due to its animation esp. bossing in a party.