I'm really not sure what to make of this change, just yet. On paper, it seems solid. I definitely get their reasoning behind it. Sch's and Blm's were practically useless in PvP, so this might bring them up to at least being usable without automatically becoming an instant liability. That said, I don't think that this will be enough to make them an competitive choice over Ast/Whm or Mch/Smn, especially because, in practice, I don't think this adjustment will do much.

In regards to tanks, War's will still be the reigning champions of interruptions, given that they have the highest burst and a 9 second stun lock (longer if they throw out a Mythril Tempest). Pld's will still have an identical stun timer to War's (single target duration, not multi-target duration), but their dmg output is far too low to cause consistent interruptions outside of a full GB or RA combo; so, they're full utility is still best realized by swapping to Dps or Healer support once they reach stun resistance on the enemy healer. Drk's will still be sidelined until they settle on what adjustments they want to go with. ... which really isn't any different from the way it is now.

The Dps hasn't changed much either. Casters and ranged will have a much harder time causing interrupts than melee players. Melee players will have an easier time causing interrupts than Tanks (based on dmg, not stuns). Same as before.

All in all, the best caster interruption combination is still War + Nin. I would like to hope that the general perspective on job utility will change a little, and tactics might get modified to reflect the viability of standard attack interruptions, but something tells me that most casual Feast players will still cling to their longstanding misconceptions (Ie: War's are only used for burst dmg. Pld's are only used for stun locking, which somehow lasts forever. Dps should only ever burst down the healer, regardless of who has the def buff, etc.).