How is BLM in new expansion?

[HaroldSaxon]

Also, with a certain PIE threshold and under certain conditions, the basic BLM rotation changes to AF3 -> Fire IV x2 -> Fire1 -> Fire IV x3 -> UB3, which means that you can use a third Fire IV at the end while still having enough mana and time to switch to UB3. With your "movement" rotation, you will lose out on 2 Fire IVs in this case, which is an even more severe DPS loss.
Another thing I want to point out is that yes, it is possible to "F1 > Scathe > F4 twice", but only if Scathe is cast directly after F1, which means that if you have to cancel mid-cast and use Scathe afterwards, the duration of AF3 will not be enough.

I've thought about it and wondered if its worth it, but you end up waiting for mana after your B3 cast, and you're enochian timer is even tighter iirc. I'm not sure if its worth it but i've not put much thought into it.

Do you have some hard numbers on this? (Potency lost/gained, what piety is required?).