What did you guys think of my Mia?

I have no idea what you're going for with that phantom speed.

Looks average except fortify res

Not bad, but Phantom Spd is a bit odd to put there, as she has the best Spd in the game and you don't exactly have a skill to compliment it. I would replace her A slot with something to get her stats up depending on what you want to build her up to be and use Flashing Blade seal, unless you've got another unit who's using it at the moment.