DXB desperately needs a third, independent runway.
There is the third runway, at OMDW, that is. I don't know why would you have DWC thrown out in the desert, while all expansion plans are OMDB centric.
Building a 3rd runway at OMDB defeats the purpose of having DWC. It is difficult to expand OMDB with all the residential areas surrounding. Unless they build the third runway in place of the Mushrif Park, allowing aircrafts to taxi in tunnels under the "E311" road.
I'd say rather than the current Cargo expansion, "all" Cargo should to be moved to DWC. Something that would piss courier businesses off... alot.
I would second the idea of moving the LCC's out to DWC, but the ill-managed Flydubai won't be able to handle the workflow. It is expected that DWC will be Flydubai's new home.