I was in there with ya, not a very fun game (only like 4 of us). Keep playing, you'll really love it when its like 10 guys playing, makes it allot funner, well I think.
Maybe one of the Dev's can elaborate, but pretty sure, no Single Player is planed as of now, going to finish the Multiplayer and get that squared. But don't think It's really been denied, but more a "when multilplayer is done"
But I'd sure love to work or test anything for the Singleplayer.
There is (was?) the GoldenEye: 00 Heaven Single player Crysis mod, but not sure if its still under development (hopefully is) but Wake will have to answer that.