Although Dow3 is very competitive multiplayer RTS, I believe a taste of coop mode would be nice, just as Last Stand mode of Dow2 did.
But Last Stand felt somewhat off the rail compared to Dow2's core gameplay, so I thinking a co-op mode with a relevance to Dow 3 game mechanic.
"Horus Heresy battle mode"
Reliving iconic battles of Horus Heresy such as "Isstvan V", players can be the loyalists to defend the area or become Traitor legions to vanquish them.
and there are numerous battles that includes Orcs and Eldars in Horus Heresy as far I concern, so all three factions can join.
I know units were very different from then, so additional skins can be released.
Never before DOW series touched Horus Heresy era, and many WHM40K tabletop fans might get interested with this, which leads to more playerbase!
Tell me what you think!