You don't really "need" gear that's any better than the content you're running. If you're not running 70 content until you've reached the point to unlock it, you don't really need 70 i400 gear. You just hit Stormblood, so at best, you should be somewhere around i270.

More to the point, you're playing through the story at a point where experience has been buffed a time or two, in addition to those 50 and 60 quests now giving exp where, previously being level cap, there was no exp to grant for those quests.

But, what difference does it make? Even if you were at-level, those quests would still feel like fetch quests to slog through, because, really, that's what most of them are. Busy work. Most of MSQ, most quests in general, are rather trivial, whether you're overleveled or not. Anywhere that it actually matters, primarily instanced content, will force a level sync on you, so that, again, being overleveled doesn't really matter, you're brought down to be equal to everyone else running those instances.

In conclusion, don't be so concerned with "gearing up" for the level you are. It only really matters to be geared for the content you run.