More the merrier.
While I'd love to have it purely based on slice of life, horror of war etc I do have a story in mind. I'm still working on the details and a lot of it will be behind the scenes (after all, the boots on the ground never hear the whole story) but there will be a coherent plot line.
Also, I will probably limit the numbers of certain classes like Snipers and Lancers to keep thing balanced. Probably one of each unless we get over ten players.