The multihit skill doesnt sell to me either. I would assume it not to work on skills because that would be too OP. But then if it works only on basic attacks its really “meh”. I mean, It’s probably only one hit, for only one mob… Even if it deals amazing 50k+ damage in total with a 15s cooldown it’s still really “meh”.
As for merkabah attribute, I have no idea, but that kabbalist seems to be getting a lot of blocks for what a normal cleric with a shield could achieve (without stone skin).