Currently the only role it falters at is healer. Reasons being lack of party buffs, no esuna, no raise, and its only heal spell is based on their current HP making it inconsistent. It could be ridiculously OP on 1 cast and almost negligible the next if the caster takes a heavy hit. Well there is 1 other option but that kills the caster.
Utilizing skills currently available its possible to make BLU nearly as competent as a lv 50 tank in ilvl 130 gear.
However it feels like a lot of you assume OP means BLU is supposed to do as much damage at lv 50 in ilvl 130 gear as your lv 70 dps does in ilvl 400 gear allowing it to solo clear any content while sipping a cup of tea.
Other things with BLU as it is currently.
Claims that status effects or certain skills don't count because they don't work on bosses. Other jobs face this as well. Its nothing new. However most non boss enemies don't have these immunities. Add to that many of BLU's AoE skills don't have a damage fall off per target like AoEs from other jobs and they easily claim a top spot in crowd control at their current level of relevant content. If you think otherwise then equip your job with ilvl 130 gear and do a lv 50 duty synced.
Some of the blu spell combos are quite OP as well at lv 50 if you pull them off. I'd like to see some combos IMO that didn't rely on status effects though. Or the addition of some type of combo mechanic that would encourage people to cast more than 1 or 2 spells primarily.