I ... don't get how arrow on blm's aoe rotation is not a dps increase?...

Your entire damage is sped up except for the umbral ice phase where you are dependent on server ticks. Your whole fire phase is sped up. I do not see how this is not a dps increase. It's not as good as a balance would be, but it's still a blatant dps increase.

I hate to say it, but if your reasoning for it being a dps loss is that it messes with your fire 3 back into astral fire and you only get 1 mp tick, git gud and learn to wait that extra fraction of a second.