BLM is a top tier class in the current meta - after all, what MMO has mages as a bad class?
I lvled all the way from 1 to 30 in full PvE gear, having 0 morale, did not use any i55/i70 gear - and i ended up with a 94%+ win rate which is pretty good imo
Now that mage is one of the two classes with reliable slow (i call heavy slow) it's better than ever; we have good survivability+kite and ok dmg
Overall i think of mage as a utility > damage class, especially since literally every team tries to kill you
You are the play maker in your team who controls the field - it's up to you to force trinkets / make calls / call out switches etc