This far in to XIVs life span? No. Wide, sweeping changes of that nature aren't usually well received by stable fanbase and it would represent a large risk with no promise of any real gain.

Refined, enhanced, expanded on? Maybe. For my buck I'd like to see them add new specifications to existing jobs to allow for a wider variety of play styles and letting people differentiate themselves a bit more than they do now.

As for new mechanics and such, I'm the wrong guy to ask for those specific questions.