8.0 is when I believe they mentioned wanting to tackle job identity so it would be interesting to see what they do.
There are two changes that come to mind atm but I think one is probably not a good fit into an MMO

Dark Knight is a job that has always used its HP for dealing big attacks
So it could be fun to manage HP by using these attacks and having the necessary self sustain to keep yourself alive along with being healed by the healer

It could be fun risk vs reward as you may expend a lot of health to deal damage during a part of the fight you are confident you can survive
I know the bloodgauge is most likely meant to represent this concept, but it isn't how I imagine it
However as a tank it might be somewhat difficult to pull off

One other thing had to do with Gunbreaker, and it's a minor change but I thought it'd be a nice touch if they made it where every cartridge you spent would result in a crit.
Because in final fantasy 8 if you press the trigger at the correct time with Squall your gunblade would go off and you would deal a critical hit