Every class in this game is fairly simple to play at a basic level and complexity increases as you explore the intricacies of the role. As long as you do a bit of research on the job and practice on a dummy/while leveling I see no reason why you can't pick up any job and play it if you wish to. I think the latter point about while leveling is something that alot of people don't do but it really does help. Personally, when I pick up a new class I look into it first and set my hotkeys up so everything is in a familiar and comfortable spot without having to rearrange it for new skills as I go along. This lets you start to develop muscle memory and familiarity with the way you're set up in a much less pressured environment (leveling dungeons).