I think you should not nerf it. Atleast do not touch the XP. That would be like taking a pee on half the player base that has not reached vet ranks yet. or buff up Xp gained in vet zones ten fold at the very least. Doing it the "quest way" would take ages and that train has sort of left already, its to late to force players to do that now when so many farmed their vet ranks in craglorn.
If your going to do something at all then decrease the drop rates on epics, because its just silly as it is, i even destroy blues to sqeeze more epics into my bags atm...