How much of a bonus to BLU skill acquisition would it take for you to attempt it

[Bonbori]

For BLU-only, synced and without echo?

100% and not a nanofraction less than that.

At the very least, if it's not practically guaranteed, I'll probably stick to the unsynced farm PFs just like last time.

While I did enjoy doing all-BLU dungeons the last time BLU was alive for a week, and even on one occasion all of the Crystal Tower raids, none of those had EX mechanics. Pug groups have trouble doing HW Extremes even unsynced at 80, I don't have a lot of faith in it being a more time-efficient method for farming spells unless a coordinated static is doing it. An unsynced group can probably get like 20 clears in by the time an all-BLU party is done progging Sephirot so unless learning the spells synced is guaranteed or nearly so, I don't foresee it being viable for skill acquisition.

For fun tho? Absolutely! I love all-BLU parties. I'll definitely try it, I'm just not expecting to get any spells that way.

I think the biggest reason why BLU's lifespan is so short is the fact they insist on throwing it into party content and the party content gets rushed for the first week because nobody wants to be left out by the time the BLU hype dies off and parties become impossible to find... It should always have been a solo job with the option to do Squadrons, Palace of the Dead and use Duty Finder for low-level dungeons and trials. It wouldn't have made it a real job but would at least give BLUs some degree of long-term usability.