I just have one forum and it's got AdSense in it and I don't display too many ads either, as my users were complaining about them from before. Well, it's not that hard to limit the ads to 3, as they don't make much money to begin with and as long as the users are happy, I don't mind reducing the number of ads.
Also, I don't plan to open up any new websites. It's hard for me to handle one forum and I can't even imagine what it feels like to manage 15 websites like you
I would probably be dead in a few months or so, if it were me(most likely scenario). I am no good with creating good content either(unless I do enough research). I am not that active in my forum as half of time I don't know what to post, as I am not watching anime, at the moment. Hopefully that should change soon.