Well the MMO was actually sort of partially FPS too originally I think. At an educated guess I would say that they've taken the already developed resources to launch this game in an attempt to help raise cash to finish development of their MMO still in the works.
That isn't necessarily a bad thing, they've been working on the other for quite a while and it was looking fairly tasty. So they could just port the art assets over, and keep whatever parts of their engine (it was already playable) necessary and then marry that with some sort of to-be-announced online match making system.
I wonder what sort of gametypes they'll have. I suppose the most obvious would be TDM, and I could see some sort of capture the flage (or, erm... artifact?) fitting in quite nicely. They could a control point war across a field just as easily, or really most any of the commonly recognised FPS game formats could be worked to fit in with the theme.