According to fan translations over at the RelicNews Forums, Dawn of War 2 will sport multicore processor support, DirectX 10 optimizations, and incorporate several elements from Relic's WWII RTS Company of Heroes (PC), such as environment destruction and the ability to occupy buildings.
While only two forces were listed in the article--Orks and Space Marines--both will feature full co-op campaigns. Though other playable races will be revealed later in the year, it was implied that not all will have co-op campaigns.
The fans also report that players will be limited to six squads at a time, at least in the campaign, though each can be customized with new items and equipment. "You really have to look out for your squads and don't treat them like cannon fodder," wrote translator Togra.
Said to be in development since September of 2005 by a team of 55 people, Dawn of War 2 is expected, at the very soonest, in early 2009. More concrete information, including screenshots, should arrive in the near future.