If i had to give PvP in this game a score, i'd say its Pi/10, the pain is low but never ending.

First of all, PvP is designed arround teamfights and not man-on-man duels and as such, the balance arround Jobs is literally thrown out of the window, or in FFXIV's case, banished into the most remote Region of La Noscea which is some corner in the middle of the ocean.

No matter what Job you pick, you will notice immediately once you enter said area that all your skills are gone. PvP in this Game gives you a "unique" set of skills, along with a limitbreak and Combat Potions which refill themselves and make this mode even more painful that it should be, thanks to those Potions fights are incredibly stale and killing Healers on your own is literally impossible unless you play melee dps and you manage to find yourself a inexperienced healer who got lost on his daily roulette and joined in on frontlines instead, which is then usually a matter of seconds before he/she breaks under the pressure.

As for Feast, as mentioned before its 4vs4 teamfights which is just a Mindgame to confuse the opposing healer on whoever makes the first mistake, otherwise its just a wild goose chase.