Just a had a thought... Seems like with every major addition to AH, the older maps end up getting cycled out anyways. Like when the CVs were added, the maps that couldn't support them went away.
With the latest release we'll have trains, maybe convoys, new terrain cover and objects, and all tied into a new strat system. Will these be incorporated into existing maps or placed on entirely new maps out of neccessity? Can you even have trains on a map like ndilses?
Not sure what it boils down to, but it seems like the new maps we get correlate with the new features we get, so it may be that some maps (like in the past) will have to be cycled out anyways.