If you read what I said above, you will notice that I said this: "if adding another player would result in a poor framerate or poor graphics, then I will understand the devs."
It's not only that. It also involves a huge amount of work (as Lar said) and therefore a lot of money...
So unless you're all ready to pay for the game years before the release (we would need millions, and the game would obviously need to be delayed but you would all understand and wait patiently, wouldn't you?), I'd say there's very little chance it'll be included in the game at the time of the initial release.
Just stick to what Lar said, it's just not doable at the moment.
But who knows what future will bring. You never know what Lar has in mind (me included)
