I take a somewhat different view of this. You must recall that US and UA were prevented in code sharing to DCA and IAD as they would tie up alot of the competition in that area.

If DL/CO/NW were approved, and I think that is still going to be a pretty big if, then I think there will be numerous instances where they will not be able to code-share.

You should also recall that they do not want to hurt American, and American if memory serves, is a very big player in TX (like CO).
Even if they are pro-corporate, they know there will be a howl of protests against this because it would hurt the average joe and jane.

I think that it will be delayed some more but that it will eventually be approved with the type of provisos, I have outlined. Code shareing on empty flights where there is overcapacity makes sense, but not when it will become a monopoly. They are sensitive to avg. consumers' complaints more than they will be to the airline union workers, who will lost jobs with the shrinkage of the overcapacity.

As for Europe, I bet they will approve it within limits, and throw American the bone of allowing them to go ahead with BA to code-share to LHR, since CO/NW/DL will have a big presence in both the French, Dutch and Italian cities.

I have no idea re Asia, Latin America, Carribean or the Pacific, but I think that DL's presence there is somehat limitied, already, anyhow(?)