The great fast paced DoW gameplay,with lots of factions to use,and great board game style ideas.
I think WH 40K Dark Crusade is a much better game than Winter Assault.
In campaign mode,before each mission,you and the other factions take turns deciding which areas to attack(and there's strategic importance in how you progress through the map because you can capture certain areas that will give you access to a starport(which allows you to travel anywhere you want to on the map instantly and attack the territories with weaker resistance),and certain territories you capture will provide you with extra and more powerful units at the beginning of missions and you can capture a territory that's rich in resources and it will give you more requisition to build units with during missions and you can eliminate a faction from the game if you capture the territory that their stronghold is in.
There will be times you will need to defend your territories when they're attacked.
The gameplay in WH 40K Dark Crusade is fast paced and if you've played DoW you'll know that infantry units are built very quickly and in groups,and vehicles are built in single numbers but are heavily armored and can kill infantry units easily but are slower to build.The races in WH 40K Dark Crusade include the Space Marines,Imperial Guard,Orks,Chaos,Eldar,Necrons,Tau Empire.
The story in the game is the factions are fighting for control of a planet named Kronus.
I'll give a bit of info about each faction.
Space Marines-They serve the emporer of humanity and want to conquer the galaxy in his name.The Space Marines are the elite of the emporer's army.
Imperials-They also serve the emporer of humanity and want to conquer the galaxy for him,but they are not as well armored and their weapons don't have as much firepower as the space marines,but the Imperials are in bigger numbers than the space marines.
Orks-A race of alien Orks are less technologically developed than any of the other races but they reproduce at a very fast race and attack with huge numbers.
Eldar-A mysterious,ancient,highly advanced race of aliens who's motives are unknown.They have been around for hundreds of millions of years,and occasionally show up,and do things(which sometimes upsets the other races)and they will disappear again.One thing that is known about the Eldar is that they want to stop the Necrons.
Necrons-Are an army of robots who have awoken after hundreds of millions of years and their only purpose is to destroy all life in the galaxy and when they conquer a planet,they will make it's atmosphere toxic so it will kill even the microscopic life.The Necrons have powerful weapons and their robots are heavily armored and they transport huge numbers of their robots to different planets using giant mobile bases named monoliths which they can even use to attack enemy baases with(the monoliths contain powerful energy weapons).
Chaos-Another faction of humanity,except the Chaos like to summon demons and they want to summon a powerful demon that's hard to kill and they have access to some of the space marine's technology.
Tau Empire-An elegant civilization who are made out of many different races and Kronus is their homeworld.They have units with powerful energy weapons(some of them can shoot their weapon a long distance) and they have good snipers and but they're units often lack armor and manuverability and are more suited to defensive tactics.
The CPU will try to rebuild buildings that you destroy(unlike in the first 2 DoW games).
Many of the campaign missions are skirmish style missions,because you and the CPU will begin the mission with no base and only a few units and both you and the CPU will have to contruct a base,units,and move through the tech tree.It's possible to rush your enemy early on and eliminate them quickly.But if the mission drags on,it will suit certain factions.If you want to rush your enemy early on and eliminate them quickly,it's easier to do that with the orcs or space marines,because the orcs can build large numbers of units quickly and the space marine infantry are quite powerful even at the basic level.If the mission last for a long time,it will suit the Eldar or Necrons because they have the most advanced technology and it will give them a chance to move through the tech tree.The Tau Empire seem a little disadvantaged because their units are so defensively oriented and the Chaos feel a little bit weak compared to some of the other factions because they don't have any real advantage.A problem with the gameplay is the factions are a little unbalanced.
The gameplay feels more exciting than in the first 2 DoW g ames because you'll have to defend your territories or fight to gain territories(you can simulate a territorial battle if you want to save time,but if you lose the battle,you'll lose the territory,but you can cheat and reload to a previous save if you lose a territory).You can take a risk early on in missions and go for an all out attack right right at the start to eliminate all the enemies.Sometimes the CPU begins missions with 2 groups of units that will try to contruct 2 bases so you'll need to be very efficient with your battle tactics and resource management early on.
The DoW style special units are also in this game.
However,the stronghold for each factions had a base that's already been constructed,with defenses and the full tech tree available for that faction.
There is also now some minor RPG elements because you can customize the weapons and armor of your commander(which effects their stats).
The game has the same cinematic presentation right at the start of the game with the humans fighting the orks and when you a victorious with each faction you'll see their ending and you'll see things such as the beautiful capital city of Kronus,and other things that I don't want to spoil for you.
Kronus has great diversity of rocky terain,snowy mountains,underground caves,desert,wasteland,jungle and the beautiful Tau capital city.
The music is okay but not as good as in the original DoW game.
The voice acting contains the philosophical quotes of the units/commanders,but I think some of them don't sound as good as they did in the first 2 DoW games.For example,even though Gabriel says his memorable quotes from the original DoW game,his voice doesn't sound as good.
Overall,it's a terrific DoW game and a great RTS game in general and you don't need the original DoW to play this game.