As people've said, older content levels you much faster than originally, so you're going to be way ahead of the MSQ.

I suggest you actually level 2 jobs at once- basically do one that you enjoy on MSQ stuff only, but also level a second using roulettes etc, to soak any xp when your main caps. Ideally keep them withing 5 levels of each other.

Ultimately, this is to give you some options when you start doing later content like raids (you can have a DPS and a Tank, for example).

Even when the newest expansion drops, you can typically get 2 levels to cap if you run dailies while also doing the MSQ.