The added game-play features you mention would make it a worthwhile venture. As to bringing the other Greek factions in line with the changes to the GCS, I’ve already drawn the unit and unit-info cards for Macedonian war elephants. I don’t know whether they already exist on some other mod (perhaps the same source you used for the GCS elephant units), but I could upload them and work on the other two elephant units if they don’t.
What's the deal with 'provincial' campaigns? Is there an option to add more campaigns other than Sons of Mars and the Imperial one? I'd really like to know, because I have experimented with creating new maps and once tried, unsuccessfully, to create my own small campaign, in place of the Sons of Mars.