The problem with this is BLU is by far weaker than regular lv50's and all-BLU parties are inferior to a standard tank/heal set up. White wind is limited, BLU has no rez at all and Mighty Guard is straight-up rubbish. To top it off, there are no real rewards for running content synched as BLU.

BLU just wasn't designed to run any content besides the Carnival. Even half the open world fates are Doom immune. The entire class design is centered and focused around just the Carnival and beating its various bonus challenges and navigating the elemental weaknesses.