If we could see numbers about activity of ever class(if it's possible), I think numbers would be different. But anyway nice to see this list
looks like marksman are rare.
marksman are static because of mana issues/need to stay still while shooting. So maybe bring back ability to move and shoot for marksmen class and see how it works.
warlocks are balancing between power and fragility, GCD update makes them weaker so maybe add some new area that explodes enemy corpses or some summoning skills (like necromancers in some games).
conjurers are super easy to grind with zarkit, but with full support setup it is harder + less exp, so maybe do something that makes supporting more rewarding.