Cool, new stuff, but not enough for a stand-alone expansion. Just two new races, new levels, and extra air vehicles.
Well, "Sisters of Battle" are just MORE Imperials, and the Dark Eldar are to the Eldar as Chaos is to Space Marines. Which is to say, they're completely different, but not dramatically enough. They're all still cool, though.
They have pretty much every Warhammer 40,000 army now. The Witch Hunters (Sisters of Battle) and Dark Eldar were added in. I don't know if Daemonhunters actually have anything unique enough to warrant their own army, but if they do, they're missing. I hardly know anything about the board game.
The only thing they're really missing (aside from the previously mentioned Daemonhunters) is the Tyranid army. Which I guess is okay, because some fans made a Dark Crusade mod that added the Tyranids in, but having them officially put in would be a lot nicer. Fans made a Tau mod for Dawn of War, too, but Dark Crusade's Tau blew that mod out of the water.
Anyway...
ALL they added was some cool, new things. The campaign in Dark Crusade utterly disappointed me. The first game, along with Winter Assault, had actual campaigns with voice acting, scripted cutscenes, special objectives and all that other good stuff typical to a good RTS campaign. They never really made any sense and had zero likeable characters, but they were still awesome.
Clearly where I'm going with this is that Soulstorm has the same crappy campaign as Dark Crusade, just with planets and gateways to travel between them. It all plays out as an extremely lengthy board game (nothing like the actual board game). The player controls certain areas of the interplanetary board, and to get more he must send his Commander to fight battles on enemy territory (when its his turn), and must sometimes defend his own territory. The player gets to customize his Commander and gets special abilities depending on his army, and that's all fine and good, but ultimately the whole thing is lame. Firstly, there's no real plot or anything. There's especially no characters or cutscenes, except for the intro which says "The Tau were really pissed so they went to the planet to kick some ass!" Yeah whatever.
My biggest problem is that, even though it's a big free-for-all, the actual levels are strictly 1vs1. I cannot stand games that do that. I remember playing Medieval: Total War, which made it almost impossible to fight alongside a teammate and there was no way to against two seperate enemies who weren't on the same team. Though that's not realistically very likely.
The campaign would've been great if battles could've involved more than just the player and his one opponent. If you're going to have a ton of armies and have them all against eachother, you ought to make it so they can all fight eachother at the same time, if a situation calls for it. What if two armies want the same area owned by another army? Then all three armies should do battle! That'd be awesome! But this game does not have that.
What I can't stand now is that the Tau Commander icon is solid red, just because the Tau army in the campaign is red. I never play as those red jerks in skirmish! They're way too damn red, and so is the icon. Friggin' red.
Anyway, the new things are cool, but the campaign sucks and there's still no Tyranids.