Wish I could figure out what I'm doing wrong on my retainer for the field exploration 13s. Item level 70, check. As far as I know, that's all you need, mine's an Arcanist as well.

Field Explore she brings me a handful of silver pieces and courel meat HQ....thats it, nothing else, same thing 5 times in a row.

Do a quick venture, occasionally she brings me something neat, mostly food, fish, the occasional housing item.

My other retainer, which I've only done quicks on since reaching level 10, with basically no gear on aside from the level 1 weapon she is equipped with, brings me tier 4 materia, mog weapons, pvp gear and even got one of the new body pieces from the new 3 dungeons that came with 2.2 .. bah.

Random system is extremely random.