Melee could very definitely see the PVP style brought over to PVE. Part of me thinks they only put it in PVP to initially test player use and feedback before they add it to PVE.

As for the mages, I expect to see a lot more of the spell evolution that now takes place (Stone 1 > 4 for example). They've done this for SMN, not yet for BLM or RDM but its possible. BRD even has had this done to their DoTs. Some spells could actually be the same button; Blizzard 4/Fire 4 for example could be the same button and switch depending on if you are under UI or AF. WAR does this already with several abilities depending on which stance they are in.

There are definitely options and they are definitely thinking about this. YoshiP prefers to play with controller himself, afterall.