Say No to those who obviously want the game to fail!
Sorry Harold I couldn't resist
But ok what can they do? How do they retain players? Everyone here seems to be an expert on how to retain players in a very niche genre of historical RTS. Not the easiest thing to get the masses in to these days! It's not like when I was young and the store shelves were covered in big cardboard boxes with war scenes on the front. CoH2 is probably the most succesfull military RTS right now and that's largely due to it being an arcade style game. I take it that's not what you guys want?
Respond faster to player concerns.
Communicate intent.
Have longer betas where all parts of the game are tested before release, not just select parts.
Focus group testing of new player experience and substantial investment in improving it (which to an extent Eugen did) coupled with a refusal to rely on esoteric mechanics that are not clearly communicated.
I gave a ton of feedback during beta under a different username. I was heavily invested in this game and in its success because it was literally exactly what I wanted. I got a couple friends to buy it, talked about it with CoH2 buddies and in CoH2.org and was generally trying to help it be the best game of could be.
And then the game came out and two untested divisions became a giant source of balance problems, matchmaker was unfinished and poorly designed, line of sight tool is still utterly broken by terrain and therefore useless. Observe was added but in a way that makes it both a potential tool for cheats because of the short time delay and also useless because almost everyone turns it off. Not to mention it was nonfunctional for over a week due to bugs.
None of the things that make this game good are new to the series, like the mix between zoom and detail or the tight unit micro and mass scale. Many of the things that make it bad are new, like massive amounts of RNG and the huge impact of veterancy.
Most obnoxious of all has been the arbitrary commitments to historical accuracy in ways that harm balance. Tank and AA performance has to be "authentic" except for their ranges, automotive reliability and full tank range, but plane availability, accuracy and battlefield impact can be riotously fantasy with no issue. It shouldn't be this hard to find a compromise between authenticity and reasonably good play experiences.
Also the mustang iv the poles use was just as fast as the p51d with exactly the same engine, but for some reason it goes super slow. That just annoys me. Takes five seconds to find that out on wikipedia but it is still an issue.