I actually considered that, but if you think about it, solo PoTD is high end content, based on which jobs were available at that given time, and PoTD was built with these jobs/skills in mind. While doing it with a lvl 60 Blue Mage, a class designed for solo content, it would just make the whole PoTD solo achievement underwhelming and too easy. Compared to people that actually had a hard time clearing it with "fair" rules.
Blues Mage has its own solo instance, that's it. I don't see it getting access to Diadem or Eureka even with higher level cap.
