how to make coh2 good:
lower infantry HP, make cover give more modifiers
lower RNG across the board
cp2 russian elite troops
fix input delay for international players IE: euro vs australian
pay some youtube celebrity to play it, and put it on sale
gg
This is a very good start at courting the "pro" community. Aggressive balance patching is also required to keep the community feeling like the game is being supported and will get better. It's shameful that games like Insurgency get multiple patches a week from an indie dev while CoH2 hasn't had an update in ages.
Additionally, for the more general population, I would probably suggest a price reduction across the board with a less Commander centric DLC plan. Cut $10 off the game price, and cut all DLC commanders to $2, and match every future DLC commander with a free commander (whether it is true or not, the DLC commander cause a lot of Pay2Win complaints, and it keeps some potential buyers from purchasing the game; a friend on mine refuses to buy it over the Commander DLC). A shift in focus to DLC skins (camo, vehicles skins like alternate turrets and swaps (puma skin for scout car with no stat changes), and coop mission DLC.
At this point CoH2 seems to have a steady population, it's not bleeding players yet and while it can be hard to bring back tho missing players, the right changes can convince players to return. The general complaints are not changing either: balance, pay2win commanders, and too much RNG. Address these and you'll see a lot of player return, then keep them here with tournament support (hell, talk to Valve about the tournament ticket thing they do with DOTA2 and add in-game viewing support of Relic sponsored tournaments).