Main quest definitely gets better. ARR story is awful but the rest is pretty good. Especially Heavensward.

The combat gets way better as you level too. Right now you're a class and it gets even better when you get your job at 30. The game picks up combat even more at 50 and 60, so yes. It does get better.

As for ques, DPS que is the worst. Healer is pretty great and the fastest is tank. Maybe try and join an FC to see if people could join you?