I think this is a serious case of over thinking. It's probably a bland cover because they didn't put a lot of effort into it. Or they/there focus group kinda liked it. I don't think it has to be some insideous marketing ploy: Its just that they did a sub-par job on the least important part of the game. I think your looking for patterns where none exist.
Dead on with that shot at Evony.
I remember seeing constant banner ads at various wikis, when I eventually got round to checking the game out I had to laugh. Suckered by the boobs.