I tell you, I'm L50 on Marauder and Archer, and guess what? I'm doing more damage as a Marauder.
Why? Nope, it's not because of the gear, neither of the actions placement in my bar. It's because I don't know how to play Archer, so I'm better with Marauder.
I'm not joking if I say I outstand Archers sometimes, so it really depends on how well you play a class.
People requiring only Archers in their parties, or only Thaumaturges in Ifrit parties are just Easy Mode lazy f*cks who want things just to accomodate their needs. I'm not gonna expertise me in Archer that much, since my second class is Pugilist, so party recruiters have to deal with it =)