They are kinda divided over the Mega Campaigns. On the one hand, everyone buys them, on the other hand, they take enormous amount of work to do. If you look at the website you will see how many projects Matrix is currently involved in.
At the same time, they are focused at their two babies Uncommon valor/war in the pacific and Combat leader/Close assault.
About a year ago, the desicion was made to focus on the new games. So, first Uncommon Valor was released, that team is working on War in the pacific now (Uncommon valor covering the entire pac theater). Meanwhile the rest are working with Combat leader that is about to hit alpha soon.
I playtested all of the Mega campaigns, and I think you will enjoy Operation Watchtower muahahaha (laughs knowingly)
If you get the opportunity, you should really buy the lost victories mega campaign too, that is the one that puts "mega" into "mega campaigns" I dont remember exactly, but I think the player gets to follow his force over 170 battles in that one.
Anyway, back to the mega campaigns, I think there is a discussion right now about letting some players create the next mega campaign, since the regular matrix guys are tied up in the other projects, but I'm not sure how far those plans have come.
(latest rumor about the "next" Mega campaign is that it will probably put the player in charge of a Tiger company in 43-44.)