TBH All of the Homeworld games have been about the Single Player experience. With MP being after thoughts, or just shoehorned in. Deserts of Kharak seems to be no exception.
For those like me that do not play multiplayer this is just fine. There really needs to be more Single Player focused story line games.
I'm not going to say DoK is a "great" RTS, because it is not. I rate it as an "average" RTS. There are far better RTS's out there. However i did enjoy the campaign. The game play, and atmosphere got Homeworld spot on. Basically the game looks and plays just like Homeworld 2. Except its on the ground. Which is kind of weird until you get used to it.
Where DoK really shines is in its story mode, music, and artwork. Sure there was some glitches, and bad game play choices (like a total lack of facing, and formations), but overall i think its a good game.
If you never played any of the Homeworld games before i would suggest to play Homeworld Classic before you invest in DoK. This game does really seem like it was made only for the Homeworld fans, and if you are a fan of Homeworld then you will definitely like DoK. If you never played HW then i can see how things would be confusing. If you are looking for a MP experience then you bought the WRONG game.
I am amazed at how some people STILL blindly invest in, or pre-order a game knowing absolutely nothing about it. Then get angry that it was not what they expected it to be, and demand a refund. If you know nothing about it do some research first, or wait until after its released, and the reviews are in before wasting your money.