Indeed. Additionally it would be idiotic to include a power increase with every single zone released and that would make no sense considering the discussion that people of varying levels can participate. I just can't see this being the norm for their updates. I can see larger updates including new dungeons with better gear, but otherwise it seems like most power increases would have to be tied to expansion-esque content.
Ideally you could do this as your 4th quarter every year and there would be no need for large scale expansions for some time. They could offer small expansions similar to SWTOR or even EQ days at this pace.