well D:OS had a quite good coverage among HC gamers... many websites (and even the most famous) spoke about it.
You should keep in mind that D:OS will never have the press campaign of an AAA game and anyway why do you want CoD players to hear about it? their reaction "well turn based combat, that sucks !! and the graphics are awful !!"
IMO spending money in just to have a conference or a stand at the E3 is a waste of time and money.
As for GOG, well I did not know that one so far so I cannot say.
They will probably be once again part of Focus Home Interactive stand at the GamesCom like last year
