How is BLM in new expansion?

[HeavensSword]

imo any of the casters aren't that amazing at the moment, any of the melees can keep up or surpass their dmg while not being penalized for movement, in the 3sec is takes for a blm to cast one spell I can do 2 skills + some ogcd skills, which adds up over a fight, if a caster makes one mistake their dps is gone, where as melee we just use another instant skill...

mobility is king in any mmo, nothing will ever change.

You're trivializing movement's detriment for melee; maybe it's because you play NIN. Movement and mechanics can still greatly effect Melee DPS, especially MNK and DRG because of how these classes work. Missing a positional, while not the same as interrupting a cast, is still lost DPS. Losing GL or BotD is a major DPS loss.

The difference is a 1200 DPS parse on a dummy vs. a 800-870 parse on an actual boss. This can get better with experience on a particular fight, but you'll never get those dummy parses in practice due to movement and mechanics.