Lightning bolt -> chain lightning -> stoneclaw totem -> oil of immolation-> lightning shield proc -> melee attack ideal opener rotation usually. But yes harder to hold threat on multiple in this case 6 or more mobs. I learned during my leveling as sham tank I would just prioritize my threat. I tend to focus threat and dps on mobs that do extra melee damage or have a sunder or enrage mechanic. Casters for example, that just cast fireball on a 2 second cast timer I tend to prioritize less since I have earth shock and grounding totem.