I suggested several times the editors from Heroes_3 and AgeofWonders:SM be used as blueprints for the editor in Dominions_3. Let's take a moment and pray.
If Events have been added into the game, events like we see in Heroes_3 and AgeofWonders:SM... then map makers could effectively make a campaign on a single map.
A campaign using multiple maps means transitioning data such as research, gold, gems, and possibly some troops with items between maps which I doubt we'll see. It certainly sounds nice... especially with a multiplayer campaign using multiple maps! Thus after a specific day research, gold, gems, and possibly some troops with items are moved for all players to the next map.
I doubt we'll see this feature... but it sure sounds nice.