Wouldn't it be Irondock? Either works I suppose...both are shorter than typing out the 2 names combined...
I would say that's mainly because the MP isn't that good yet.
There are certainly issues with the MP....here's the thing though....
Sins has a very streamlined gameplay...it is fluid, fast, and efficient...the UI is very good, zooming out works flawlessly, and if you care to develop the skills you can macro and micro pretty well without having to have an insane APM...in short, the game is quick to learn, quick to play, and accessible to a large audience...
On the other hand, it lacks depth...while the lore/backstory is very intriguing, it isn't explained that much or well-developed...there are no "deep choices" tied to morality, ethics, or ideology...most tactical "choices" are superficial, with only a few true decision trees (cap/titan abilities, SB upgrades)....again, these are the types of things you need for an excellent SP experience but aren't necessary for MP (in fact they can sometimes get in the way)...
This is why I say Sins is more an MP game than an SP game, because I feel it has more MP potential than it does for SP...
But, the devs are adding more to the SP...and probably for the better since that is after all where most of their players are...the DLC focuses on adding to the "holes" in the SP experience...more planets and more meaningful planet bonuses/artifacts adds to the whole exploration component of the game...add in planet specialization, and you are introducing another element of decision-making or choice (hopefully it won't be superficial)...
Elements like a campaign or expanded diplomacy would also be great DLCs as they would also enhance the SP experience....but only time will tell whether those get realized or not...