After playing with the new emnity now for a good day I have a few observations:

I used BB only as an opening combo for extra threat at the start of a fight with unchained and berserker. After that SP>SE>SP>SE repeat. I noticed SE would fall off if I tried to weave some BB in between. I honestly didnt need it on Ultima EX or any of the new dungeons. I only used it as an opener (and for picking up certain adds like in Garuda EX)

It has its purpose. I'm not unhappy, I would have preferred SE debuff to last 20 seconds the same as SP, but oh well.