I aggree, when you get down to high level content no job is inherently complex enough to hinder the player. At this point you already know how to play it, their rotations aren't variable enough for that difficulty to be an argument.
A job might be more difficult to learn but, outside of external factor like ping that can make some jobs hard to play, none is difficult to play in a way that would hinder a savage raider.
A fight might make some jobs miserable (big downtime on jobs that need to build ressources by attacking, such as RDM, or MCH for example) or that force you to disengage or move a lot (which makes it harder for caster, meaning for RDM).
But those are fight related challenges, not jobs. Their inner rotation and complexity has nothing to do with it. In that last example, RDM would be 2 button presses for the whole rotation, the need to move preventing you to cast would still be just as difficult to navigate around.