Why do you think every game that Blizzard releases is an instant success? it's because people are still playing their previous games 5 years after they're released, and it's not the single player campaigns they're playing over and over.
I've got to disagree with you here, as I'm currently playing through the Warcraft 3 campaigns (yet again) as we speak. Generally about once I year I load them up (yaay for the last patch removing the need to keep finding my CDs) and play through the storyline. Not once have I ever logged onto Battle.net or played any other variant of multiplayer with the game. Not with Warcraft 1, Warcraft 2, Warcraft 3 or Starcraft. In fact, the only Blizzard game I have played online is World of Warcraft, and well, that's kinda part of the package *grin* Many of the folks I know in my raiding community in WoW have played through most of Blizzard's games, and still do occasionally. I can count on one hand the number of them that play online in any fashion. They play them for the gameplay and the campaigns. Blizzard games are instant successes because they've established a very long and polished reputation of releasing extremely solid, well designed, easy to play and enjoyable games. The massive success of their products has much more to do with the very large single player audience and much less to do with the considerably smaller multiplayer crowd.
Take Starcraft, often lauded as the champion of competitive multiplayer RTS. If you look at the total sales numbers of the game, and then look at the population of folks playing it online, even when at its zenith, whether competitively or not, I'd bet euros to dollars that the multiplayer crowd is dwarfed heavily by the single player crowd, and that's for the game that boasts some of the highest multiplayer saturation out there for a strategy game.
I agree that the forum whiners are more than annoying, but I don't think that's a reason to completely neglect multiplayer game balance like some people here are suggesting. just my 2c
Not once has Frogboy or any of the IC folks (on any posts I've been able to get in and read through the forum DOS) said they have no intention of balancing game issues. They have said that they won't be catering to the hardcore multiplayer crowd (specifically in response to a few vocal whiners), or prioritizing their issues beyond what the issues themselves call for. There are a very large number of things they want to do with the game, and anyone who's been with Stardock for a long time will know that they really do add so much to a game as it progresses. The balance issues are somewhere on that slate to be addressed, but they are prioritized appropriately given the number of things they want to do with Sins, and the size and distribution of their customer base.
Yes, single player issues are going to have a heavier weight, because there really are that many more people that utilize it as a game mode. But again, if you've seen Stardock (and Ironclad as well from what I've seen of them so far) at work, they have a way of squeezing a WHOLE lot of adjustments into their updates, and I've no doubt that as soon as they have the available time and man-power, they'll address balance issues and anything else they can to make their games better. It's what they do, not only making some damn fine software, but constantly improving it. People are just going to need to have patience and realize that their issues are not ZOMGENDOFTHEWORLDALLGOINGTODIEEEE!!!1!1! and enjoy the game for what it is while they wait for the inevitable update.