It seems like the default party set up for most of these fights has become a party with a PLD, BRD, WHM and RNGs. While this may be effective and "safe" I feel like most jobs are becoming more and more useless and superfluous. I know you can play a job you don't really like to join the battlefield to get gear for your favorite job, BUT I've feel like this has resulted in me just idling my favorite job than doing any content. Even difficulty levels(Normal and below) where other jobs (RDM, GEO, DDs, etc) can take part we still see players demand rangers and plds. There are a few exceptions like delve and incursion, but seeing as SE's "end game" seems to be releasing a new high tier battlefield every month, I really wish they were more friendly towards other jobs.

What could possibly fix this? Maybe if the battlefields had restrictions on only being able to take unique jobs into the battlefields, that is, only 1 of any type of job is allowed. This would force players to use those additional slots to take in jobs that aren't used much. Otherwise you might as well combine RDM BRD COR and GEO into 1 job, all DDs into RNG somehow and PLD and RUNE into a single job as well.

I don't know, it might just be me, but I'm finding this game more and more boring the more jobs are excluded. FFXI endgame (75 cap days and even aby days) were some of the most job friendly days. You could do anything and play any job you really loved. It gave us so many combinations and so many jobs to gear.

Or maybe it's the player base. Maybe SE never intended these end game battlefields to become stagnant and mundane. Personally I have been approaching these as solo challenges. I've had more fun soloing them on pld, rdm, bst and nin than any party, but even that gets old...

tl;dr: Delve is old, incursion needs more goals, and high tier battlefield job discrimination is making this game stagnant and mundane.