I don't mind the challenge, except I feel that the Mist Dragon is too unforgiving for it to be part of the MSQ.

Difficult Side-content is fine, Suzaku is not MSQ nor is Alphascape, and that's entirely fine. That bit of content can be skipped if the player can't hack it. MSQ, however, is kinda required for everything else in the game, and it shouldn't be so difficult.

But Mist Dragon is tuned just a wee bit too high for an MSQ dungeon, just a wee bit unforgiving, and 1 group member's mistake can easily wipe the whole group with that directional AoE or how the healer getting clipped by an AoE is almost certain death if you don't have a RDM or SMN in the group with you.