making sure you're properly generating threat on Hard mode content will not allow you to use this rotation whatsoever or the heals will pull aggro almost immediately.
tanking HM Ifrit and garuda, i use BB combo x5, then start mixing in main>se combos every once in a while when im Main tanking. Also, contrary to what most would say, do not blow inner beast every chance it is up. monitor what abilities the boss is using at certain cooldowns (such as incinerate) and use it after that, allowing the healers a bit more time to react to the massive damage that was dealt to you.

If you're offtanking in said fights (primarily garuda) use maim>SE combo for a while just to increase dps, and blow down dps cooldowns (keep defiance off for this stage)

when you know the adds are coming, switch defiance on, and then us BB combo to hold aggro. multiple targets should hold aggro with one or two OP then a steel cyclone. I've had no issues with this thus far in Full party hardmode settings.