I mimic the sentiment of MCH being a good choice, though I find it has as many things to consider as you would on SMN so it might not be suitable. That leaves BRD as an alternative with a similar skill set.

My next vote in would be DRG. A four step rotation to maintain BotD while keeping up your debuffs on the target and buffs on yourself does require a bit of thought in your future planning and gives an interesting flow that can be hindered dramatically with the changes in the fight. I find it highly rewarding to play at high level and be able to consistently pull off good numbers. It doesn't really get too fun until the 40-50 range and then picks up even more in the 56-58 range, so that may be something that might turn you away thanks to the small grind associated with it.