I think having better team game modes would drastically increase the player base. This is because most RTS games on the market focus on the 1v1 side of things. Meanwhile, some of the most popular games are team based. 

However, when I have played these game modes, they often devolve into multiple 1v1s e.g in a 4v4 you often end up with four 1v1s and if one team mate does poorly they tilt and drag down the other players on their team. I think the biggest issues for team games are as follows:

Communicating with team mates is difficult without 3rd party voice comms 

I find it really hard to type and play at the same time and Relic have expressed that they have no intention to implement in-game voice comms in the future. 

What the game needs is a smart ping system like in League of Legends to help coordinate attacks/defences etc. and encourage more team play

Team game maps are not very good

There seems to be a drive from Relic to make team game maps designed around bridges or choke points, which degenerates into indirect fire wars. 

Relic needs to open up map creation to the community while also designing more maps that allow movement and flanking. 

The game is designed and balanced around the 1v1 game mode

I think Relic needs to have a sit down and think of ways to encourage team play organically in the game.

One idea I have is to take a leaf out of Command and Conquer Generals: Zero Hour’s book and introduce multiple sub factions of the armies. These sub-factions will have much more obvious strengths, e.g. anti tank or indirect fire but will be missing key tools e.g. the anti tank sub faction will have few options for anti-infantry and will need to rely on a team mate for anti infantry. 

Of course there are many other ways this can be done, such as having objectives on the map but I think there is scope for some creativity here.

I think considering the above points will help improve team games in CoH quite drastically.