I reckon PvP has the potential to strengthen and solidify the FFXIV economy as well as diversify the need for gear.

There are three prerequisites that i foresee in order for PvP to fullfill this much needed role:

1) Stats need to be relevant to each class beyond base damage on weapons.

2) Multi meld gear useable in PvP

3) PvP lvl brackets every 10 lvls:

a) 1-10
b) 11-20
c) 21-30
d) 31-40
e) 41-50

With these three conditions, players will have reason to use lower level gear with multimelds of the appropriate grade creating a huge demand for mult meld gear and materia of all lvls which in turn translates to a boon for the crafting community as much as the gatherers and spiritbinders.

And if the stats were better balanced, then we might see strategic statistcal builds develope that have a greater afect than stacking base dmg.