My club has, over the last few years, run four separate campaigns for 40k, the last of which I organized. Suffice it to say, mine fell flat on its face. I think, however, that I've a theory as to why.
Lack of focus.
All these campaigns have run on the principle of having a narrative, and assigning a winner. I think, that after a few times, something needs to be changed. Okay, so it's a bit more complicated, but that'll do for now.
So I've decided to shake things up a bit. The next campaign will forego the narrative bit entirely; it will, in essence, be a tournament spread out over several months (to accomodate everybody's schedules, more than anything). I will do some meddling with the basic scenarios (bringing the two tables up to six, for a total of thirty-six possible combinations), but will otherwise leave things as they are. I will also encourage lists ofg a more competitive nature than are usually seen.
And where does this leave the narrative aspect? I'm glad you asked. And the answer is, 'down the road'. See, I'm also planning on a real campaign, with a map and four or six players, in which i can go nuts with weird rules and scenarios, without balance being such an issue. But more on that later (hopefully). I've got school work to do. Toodles.