BLM Question - To Blizz, or not to Blizz?

Post 4.2, should we be casting B4 as part of our normal rotation outside of our opener? I know there was a heated debate in early Stormblood, with lots of numbers, spreadsheets, and calculations which indicated skipping B4 was optimal due to the inordinately long cast time which reduced our overall time in AF. I know people will say that skipping B4 means you won't have a foul ready at the end of your UI phase, or that you won't have a full mana bar and risk the chance of only being able to cast four F4's instead of 5 if you skip B4, but I never run into the latter. I think what ultimately is the deciding factor here is what keeps us in AF the longest in a fight. Is it skipping b4 and going right into AF, or is it having the umbral hearts up to cast that extra f4 in AF?

Please , feel free to enlighten me on what the best course of action for us BLMs is as it regards B4 in our rotation! :)

Even though the DPS gain of each individual B4 is small, it sums up and becomes an overall gain during the whole fight. So yes, do B4 still. Sometimes skipping it is benefitial but those situations aren't common.

Be the ice mage you've always wanted to be

Should be using it when you can times where you would skip it is before going into massive down times such as tsu ex where you can squeeze in some more f4s before being stunned for second phase. With the changes to umbral and transpose these situations are even more rare than before so I wouldn't worry too much about it.

Skipping b4 is a gain, but only if it doesn't impact your MP. So b4 is worth using 99% of the time unless you're good at counting your MP tics to figure out where you can skip it. It's always much safer to just use it because slipping up a skip even once will be a huge deficit.

at low spell speed high crit dh it could be worth it i guess but even then your gonna want those extra fire 4's across the whole fight.

as others have stated there is times when you could skip its cast to get extra fire 4's before something jumps away or dies.

probs most sensible place to skip it would be with leylines up but then your running a higher risk of missing a tick and losing casts.

overall having a smoother rotation with all elements lining up is better than a more random mp tick rotation.