I had a great deal of fun in the beta I got to play every faction and I have some additions I would like to to see to make the game better in the long run.
There needs to be in game voice chat. It will be far easier to grow a community when you can communicate with people. I have not done extensive research and possibly this is in final game but I think it is an obvious need for a team game and without it, it makes 2 and 3 vs 3 matches frustrating and near unplayable as you are left to intuit strategy or waste time typing in chat.
I want to see videos showing how each unit and structure should be used for each faction also how to grow each factions armies and build them effectively. If you borrow anything from mobas or dota games the in depth video tutorials you get when they release heroes is the thing I think universally everyone would not mind. Informing people how to use the units and structures properly and some overall faction videos that go over beginner intermediate and advanced tactics will help grow the community.
These things are essential if you want to get more then people with a passing interest to grow the community. I know every campaign has worked in this capacity and community members will likely post you tube videos but having the developers show you how things are intended to be played helps a lot of the nerf this buff this rage discussions and allows for more understanding that will lead to a cleaner balance of the game in the long run as opposed to a reactionary nerf or adjustment to the communities feedback that is based on a lack of understanding or trial and error. In the end having clear and complete tutorial videos helps people on the fence who have not purchased the game make the effort to learn and put them over the top.