There is nothing "unfair" about this encounter. There is nothing "unfair" to DD casters about this encounter.
Not to sound rude, but if you are having issue on this boss then it is yourself, or the party you are with.
It is a super easy repetitive pattern repeated over and over. If youre a caster you just learn the pattern and know when to cast.

2 SMN vs the wall:

https://www.youtube.com/watch?v=QJ7Ymx2BiQg