If you'd like to do all side quests (IMO, some of them make more sense if done at the proper point in the MSQ) but don't want to overlevel too much, you can use multiple classes. One of the best features of this game is that it allows you to have all classes on a single character. Pick up a second and maybe even third class, and alternate between them while doing quests. If they are different roles, you'll get the bonus of having some flexibility when queueing for dungeons as well.