Thanks to the newest site update, we now have the tools to moderate clans, including banners.
Clans with obvious trolling banners (paint-drawn penises, portrait photos...) will lose their rights to a banner, and will have to purchase them again.
Clans with banners that we deem ugly will have the current banner removed. If they upload the same banner again, they will have their banner rights removed.
There are no specific guidelines about what we consider ugly, but as a rule of thumb you should avoid anything that stands really out of place (photos, fluorescent colors, modern fonts, plastic-looking banners...). If you are unsure whether your banner is acceptable, come ask me or other moderators in IRC.
Without even bringing up the fact that this post is from 2012, he only specifically says no penises nor portraits.
Where we get into the gritty details is the definition of an ugly banner, (without posting a picture of Panos) personally I feel that one person isn't a good enough judge to deem whether or not a whole slew of banners should be trashed, as a lot of the banners you pointed out didn't contain any of the BIG NO-NOS