In one of the recent mesa sean vids he did mention that bungie is discussing the possibility of getting rid of the plans for D3 and scrapping D2 and just bringing all the content from 1, 2, and any they have developed for 3 in one game that just constantly gets updated all the time and just calling it Destiny, which i am extremely in favor of. The was also a lot of talk in the same vid about some old strike maps returning as new Shadow Keep specific strikes as well as a lot of focus going into crucible and pvp in general so i would expect to see more maps in year three.