First of all you have Sephuz's Secret so 1st thing i'd change is Demonic Circle -> Shadowfury (honestly you should pick it even without the ring for M+).
Second thing is changing Eradication into F'n'B. Your ST will suffer a bit but i think is mandatory for AoE trash packs.
How i do in M+ (personal experience, if i'm wrong i'm open for suggestions):
2-3 targets (no need to interrupt spellcasting in deffinite situation e.g. healing spells in BRH or MoS):
Immolate all targets -> Shadowfury (stun always welcomed + ring activation which is reason of usage) -> Havoced Chaos Bolt (Cleave) + Incinerate (AoE filler)
5+ (no need to interrupt spellcasting in deffinite situation + trash kept in one place):
Stop using Chaos Bolt for RoF (+15% dmg trait helps a bit here) + Immolate targets and use Incinerate as filler.
I think this let you improve your AoE dmg in M+ a lot.