As a GNB main, I think the three jobs that need buffs the most (in order) are:
1. BLM
2. Dancer
3. GNB

With BLM needing buffs the most, then the other two. I think these three are the weakest jobs in CC from my initial impressions. Then again, I can only truly speak for GNB. GNB feels very unfun to play. Also I never feel threatened at all by BLM and DNC, regardless of what job I'm playing. Maybe DNC provides support or something, but it's really unacceptable that BLM feels like a non-factor in every game I face them in. As for my main, GNB, we're a tank that has no CC and no reliable sustain or mitigation.

Imo these three jobs need some sort of attention from the balance team. Most people I've spoken to seem to agree, too.