Monk is my least favorite DPS. The positionals are annoying, & losing GL stacks is frustrating. It might get better at higher levels, but I would't know. Machinist feels OK so far, but the level 70 rotation is not something most people can figure out with a glance at the job guide.

There's no reason to avoid main quest as healer/tank. Sure, they might take a little longer to finish solo content, but it's not severely worse. As a tradeoff, they get much faster queues on the duty finder. That more than makes up for the slower solo content.