That's what I was trying to say. BLU is not the only job which can go to old content or the only job capable of playing with non-standard comps. RDM is a full job with healing ability, solo ability, good dps and a higher level cap, which make it a great job for meme runs and challenges. Tank only runs have been done since ARR. Achievement rewards for doing raids differently have been requested before and they didn't need to be class specific.
It seems like BLU's only purpose is to introduce new ways of playing old content to people who lack the imagination to challenge themselves.