Difficulty is subjective, one would say lining buff/oGCD in the rotation is more difficult than a class with simple rotation but heavily impact by mobility, some would say the other way round. Which job a player found more difficult should not matter and should never take into account interns of balancing. Even if the dev found a way to gauge job difficulty, and giving more damage to those job, is this a form of rewarding or hand holding. Eventually, it will become the meta and only job that “relavent”, this, job difficultly should never be a factor.

However, i do think “damage uptime” should be consider, just have to be very carefully with it, it should only count as downtime where there is absolute no way of attacking. I.e. melee that got push so far out, or range/ caster have to go on full mobile not even a single no cast skill can be use.