I can say that when I first found Combatace, what immediately drew me toward the downloads section was the full campaigns, such as Operation Desert Storm and Operation Darius. For two reasons:
1- The campaigns normally include lots of planes and missions tailored to them, so there is variety in play. And if you can be bothered with learning some file editing, you can add whatever planes the campaign doesn´t include. So these whole campaign packages are a fairly user-friendly way to get into the modding scene, a comfortable stepping stone toward more content.
2- Because they are put up as a whole package, you can normally expect everything within to work as it should, which is the main worry of anyone that´s already been working with mods for some time.
Despite the huge file sizes, I find campaigns simply the best, most straightforward way to get modding content for the game. I can´t speak for every single other player out there, but since it was mentioned that the content is so fragmented... perhaps putting together campaign packages would help create some community impact.
Also, more choppers, please!