Honestly, I think the trials already ask a lot of the average player. When I did Zodiark I was grouped with several other first timers and after multiple wipes we never got him below 40%. I have similar tales for just about every trial I've queued for in the MSQ where the groups are predominantly people new to the encounter. Dungeons generally haven't been bad except for The Burn (only the tank was experienced with it), which after numerous wipes I thought I was going to have to re-queue for but we finally managed it.

Were it not for the fact that the content is mandatory for progressing through the MSQ I'd say go nuts with the difficulty. However, since it is, as far as I'm concerned some of it could stand to be toned down some. Now that they're adding trusts for (eventually) everything hopefully there can be more of a MSQ-mode for people like myself who just wanted to experience the story. Makes me wish I'd waited a year to start playing because trusts have been the best thing ever for my enjoyment of the game.