The only problem I see with mundras is with the recast, and 2 that will always be used (Huton and Suiton) that only leaves time for one other mundra before restarting the same cycle, and IMO that will almost always be Raiton. Sure you can Kassatsu for an extra mundra every 2 minutes, but in general I see most mundras being very situational and not of much use.

Even in an AOE situation, unless its a constant move the mob battle, almost always I would use Doton.