I have been working on a "Founding of Durotar" like map for some time, but there are many features and quirks about WC3 that are annoying at best and at worst force me to rewrite my ideas. I was thinking about jumping ship to SC2 but I'm finding it hard to find answers to certain questions. The most important being weather or not the "multiple maps" system works or can be done in SC2. The trigger actions don't seem to be there but hopefully that doesn't mean anything. Can anyone enlighten me on this issue?
Yes, it can probably be done. SC2 supports both offine, and now with patch 5.0 online map-to-map loading. You would have to utilize bank files a lot to get this system to work correctly. It has been a while since I've played the Rexar Campaign, so I think loading the maps all works similarly.
For example, say you kill a pre-placed mob on map 1, then go to map 2, then back to map 1, the pre-placed mob would return unless you specified that it died via bank data. Also the fog of war would reset each time you load into a new map.
Offline map loading trigger: "Set Next Map" action
Online map loading trigger: "Online Map To Map Load" action