Dawn of War has a good Combat system but the resource system makes it too easy to turtle
A simple way to fix this would be to have the strategic points (source of resources) decrease in value over time, with a final value of about +4. This would keep the game somewhat less prone too turtling, as you will run out of resources eventually and not be able to replace turrets/mines.
Another fix would have been to make the buildable zone smaller. You should have to expand to get all of your building built. At least 2 strategic points should be needed, making a much wider area to defend, and therefore making it harder to turtle.
However if online your opponent doesn't turtle (about 1/2 the time) the game is actually very fun with tactical battles, decisions, and various abilities to use.
If either of these solutions is used in DOW 2 I will be greatly pleased.