Black Mage is fine they just have to learn to deal with mechanic. This reminds me of T6 where the Black Mage potency was 10% potency higher than the Summoner and SE buffed them as an over reaction becuase movement affected there damage. I think Black Mages just want to deal hard hitting damge without any cost. A lot of jobs have built in weaknesses as Summoner can't spam there hard hitting abilitie without having DoTs up and going into Dreadwrym Trance which require Aetherflow thats on a 60s cool down. Black Mages hard hitting abilities are for the most part spammable they don't have internal weaknesses so they have an outside weakness where movement affects there dps. Black Mage already has 20% more single target potency than the Summoner any more and it'll obliterate the Summoner.