I leaning more toward it being a reference to green mages. The connection between the three leaf clover and greenmage has already been established.

Furthermore, the lead into Dawntrail is about
a viera returning to his homeland. Greenmages were a viera exclusive unit
in prior additions of Final Fantasy.

The job is not going to be anything like the support class it used to be. We know it'll be a ranged damage dealer instead. It'll be interesting to see how Square Enix will make greenmages unique from the other casters