I've gone into this in a fair bit of depth in some other threads so I'll try to be concise. TLDR: I'd actually gladly take some fresh devs over what we have now. They might make things worse, they might make things better, but at least they would have some fresh ideas and the game would see a shakeup for it. The current job design team of 4 has had 1 member change since the release of ARR, and perhaps more importantly, it's never increased in size to keep pace with both the scale of the game and player base.
It's not really fair to blame this on the job design team themselves, either Yoshida is spending his budget badly, SE's bean counters aren't giving him enough money to invest into the team and actually hire the right people (Which will involve competing against potential gacha game bonuses) or Yoshida himself blindly thinks his team has everything under control and the current status quo is fine.