Zipper isn't planning on stopping all the support they're giving to MAG anytime soon. The developers have a number of new content coming down the line, most of which will all be free.
One of the biggest requests from the community is for the ability to have all three factions fight on one map and Zipper plans to deliver that later this year. That DLC will be out closer to the end of Summer, early Fall but you can expect a number of other updates before then.
For starters, one of the new features will be "Clan Wars." Clans will be able to challenge other clans in a best of three battle. Challengers will attack first and then roles switch until an overall winner is declared. Clans will also be associated with leaderboards which will give players a chance to back out of a challenge if they see the opposing team is too strong.