Yeah, the limit is 22, but I also think it should be 25. The only problem would be that the 25p map might be a bit too popular and there will be a lot of 25 player maps with a few players.

I am totally fine with that! The less people, the better the country you get! But in reality, I do think that this could be a problem. However, if you go through the game list, there are not that many player created games. You need to have High Command for that, and there are many people not willing to pay. That narrows the field down a bit. In addition to that, High Command members can only create one game per month. Also, there are huge numbers of Clash of Nations maps in the game menu, and most of them get filled up pretty quickly. While the Historic World War map would not get filled up as quickly because of the imbalance, they would get filled up.