PvP is horribly unbalanced between the jobs right now in the new frontlines system and could really use a fix. These are my ideas as possible fixes and will most likely be slightly biased in favor of casters while being unfavorable to Bards. (only reason i made this is because i can't find a post for it anywhere.)

GLA/PLD- Provoke should switch the target to focus you for 5-8 seconds.

MRD/WAR- Honestly think MRD/WAR are fine as is if someone else wants to chime in on that one be my guest.

[WAR roommate's note. WAR is fine, I enjoy being OP] >:3

PGL/MNK and LNC/DRG- They shouldn't require to be in the proper positioning to get the stance/weaponskill bonus thing they get. (not sure about DRG with this one but thought it would be fair for both to get) Maybe apply a heavy effect with jump? Idk just seems like it would give them a way to catch a fleeing enemy a bit better, and it still has a long cooldown.