Warhammer 40,000: Dawn of War 2 shrunk the classic RTS down to squad-scale, presenting its battles as a series of close-range skirmishes between at most half-a-dozen units on each side. If you miss the larger scale and variety of factions in the original Dawn of War, the Codex Edition mod, which just released version 3.0, is for you.
Its focus is making Dawn of War 2 into "a more immersive, fluff-accurate, and realistic experience". It increases the range of weapons, adds base building (though unlike the original Dawn of War, base building isn't connected to research), ups the population capacity, and adds new units, including super-heavies like Imperial Knights and Gorkanauts. The zoom distance has been tweaked as well so you can pull back and see more of what's going on.
As well as reworking the existing factions with additional units, four new factions have been added: Necrons, T'au, Grey Knights, and the Adeptus Mechanicus. The terrain has been upscaled, the UI reworked, and existing units rebalanced so that, for instance, the Eldar and Space Marines move faster.
It's a comprehensive overhaul. Given that so many of the changes bring Dawn of War 2 more in line with a modded version of Dawn of War 1, which is still the best 40K game around, I'm not sure I need this particular mod myself. If you're more of a Dawn of War 2 enjoyer though, this might be for you. To install Codex Edition, you'll need to own Dawn of War 2: Retribution specifically, and you'll have to have it on Steam. You can Codex Edition from ModDB.
