I have to say littler servers. I’ve just finished an excellent North African campaign of 3v3. All maps were hard fought and close. There was none of the stuff that usually pisses people off. No arty-spamming, spawn camping, panzer-bitches. None of it. And, no coverts or soldiers.
Smaller servers require people to concentrate on the objectives, because if you don’t, then it’s game over very quickly. I think once you have 10 or more people on a side, it dilutes the game and lets people do what they want. Smaller servers don’t allow that and essentially force you to work as a team.
I’m gonna keep looking for smaller servers because in my experience, they consistently provide better games.