It's happening, and it's being created by the franchise's creators, Zipper Interactive. This trailer's pretty heavy on CGI but it should give you a taste of what to expect from the fourth entry in the SOCOM franchise. Guns, shooting, and lots of squad control.
On a personal level, we're not particularly huge fans of SOCOM. However, we wouldn't turn down the opportunity of getting into it. Especially when MAG was so enjoyable.