As Lar explained in the topic
I'd love to see a coop-mp (for those who have not seen it), multi-player support was put on hold due to the difficulty reconciling that style of play with the complex story and quest system they wanted to create. As it is virtually impossible that they will be dramatically changing the story or quest system at this point, multi-player support before release is extremely unlikely.
Lar did use the work 'hold', though, so it at least leaves open the possibility that they may at least be considering a way to add some form of multi-player support in a hypothetical later patch or expansion. Maybe.
If they have spare time after release, though, I'd rather modding tools be given priority over multi-player support, if it boils down to a choice between the two (which it probably will not, as there are other factors to consider in either case).
