Before Flare Star came around, the Duels were more of an actual challenge for people to get things with and people had to actually show some form of skill. Nowadays it's just "Buff the crap out of Flare Star and watch damage go BRRRRR".

I think it's still unintended for Flare Star to be used in this fashion since it was meant for raid usage(Dal/CLL/DR). There's also the fact that it's restricted to RDM in particular due to Ordained granting higher max MP so you don't run OOM the moment Flare Star is popped for 9000.

Change my mind if you think I'm wrong that Flare Star should be removed from Duel usage.