Having been around for the great Twilight invasion a few years ago, I find myself more and more concerned by what appears to me to be the mass cloning of chars from other places in literature (comics included :) ).

I feel that as a springboard the odd char 'inspired' by a favourite personality from elsewhere is fine, but once you start copying these large groups, they bring their pre-existing relationships with them, and since we've banned that in the context of HP I find it ridiculous to ship it in from elsewhere.

We had for some time a "max. two chars' images from any one show" policy for faceclaims, and I believe something similar should exist for other fictional sources, or else we're simply a samizdat facility, endlessly reprinting adventures coined elsewhere.