Mercenaries 2 creative director Cameron Brown, in an interview with Next-Gen.biz, said, "While we don’t want to delay the game, and we certainly don’t want to disappoint anyone--and we’re keen to ship the game and move on to Mercs 3."
Pandemic, now owned by EA, will most likely set to work on another sequel.
What about a Wii version?
When asked about a Wii version, Brown said:
I personally would love to make a Wii version of Mercs. I think we’ve had a lot of discussions internally about how we would do that and how we would use the controls. I would love to make something that was really unique to the platform that uses the universe of Mercs in a way that was unique to the Wii. I think you could take that kind of really over-the-top explosive attitude and do some pretty interesting things with the controls. Yeah, I will neither confirm nor deny anything about developing Mercs for the Wii but I think it would be cool."
Don't take this as a confirmation, though. Developers love to talk about the unique ways they'd use the Wii controller. Mercenaries 2 is set to release in August.
Next-Gen.biz: Pandemic Hints Mercs 3, Mercs Wii