So about Balance.

[snipski]

Machinist is really good in Rival Wings flame thrower in start of mid fight is super useful and the knockback can knock ppl out from edges that is usually a one shot move.

The only healer that needs to be tuned down abit id say is Astro good Astros are a fucking nightmare to play against. If you are a good healer in feast you wont have any problem to climb the rankings in feast because the carry potenial is so much higher then the other jobs.
Still not many ppl seem to play Healer at least on Chaos Data Center.