I would 100% main BLU if it became a 'real' job. I'm trying to get all the music scrolls in the game so I had to defeat all three of the major bosses in the carnivale to get the scrolls associated with the questline. I honestly didn't want to, had some good friends +my partner power level me and get me a bunch of good spells because I found the progression to be a pain for solo play, but I ended up having a lot of fun with it in the end. Being able to mimic any role and having so many rotations to choose from kept the whole ordeal fresh and made me miss it a little once I popped the scrolls and never looked back. Just let them be an all rounder with limitations in MSQ.