Different maps are pieces of a bigger map in every campaign. So what if we devs use all map with 3-4 times more players and multiple targets mod like assault.
Biggest problem about that will be coordination.
Why no? 1. The combat density decreases.
2. The developers have not yet filled out all the maps completely (you may notice how in Normandy, on the urban 2x2, when a new map is added, a bunch of buildings appear on an empty field).
3. The game doesn’t work well with a lot of dynamic objects, so it won’t work fine.
But in general, I would like something global, but it not will be soon.
It would be cool of course. But I doubt this engine can handle something like that.