There are several things that really annoy me with the design of the campaign that I hope Relic chooses to rectify when and if they release an expansion. Quite frankly the only good thing about the campaign is the rpg like gear system. Limited mission types, boring mission design and boss fights did not appeal to me as much as they might have. There are some things I'd like to see improved and added.
First and foremost more unit variety and more squad choices. Coupled with the ability to deploy more than one fighting force at a time. It would make sense that any continuation of the DoW2 campaign would allow the player more troops. Rhinos and Predators would also be a welcome addition to the roster for a new campaign. Fully customizable squads, not just the squad leader. I felt that one weak point of the campaign was the notion that the only reason for taking missions was to get a piece of armor or to preserve a factory whose benefits were rather pointless. I would wish for the return of the campaign map system from Dark Crusade. Perpetual squad reinforcement on the field is also a bit annoying. I'd prefer to see tougher marines whose loss would matter, necessitating the player to maintain levels of training and recruitment (perhaps a levelling system whereby each initiate has to earn their way into scouts, marines, terminator honours ect...)