Hun, hate to break it to you, but there's nothing wrong with OC's. Honestly? What would TDI be without it's fans? You can complain if people draw stuff that has NOTHING to do with TDI that ISNT in the TDI style, you can complain. But i mean you can't honest sit there are say that NOONE draws TDI characters at all. That's not true in the least. If anything, you should be saying that the spot has been override with pointless life stories that none of us need to know about. :I
But again, who cares if peope make OC's? It's i the good nature of TDI and arent making something off topic, i think it's perfectly fine.
OC's are a BIG part of showing your support for a show. Witout OC's, this place would probably be override with life stories and stupid fights about life stories.
Also, OC's help us to understand eachother better. Gives us more to talk about, let's us express ourselves freely by letting us recreate ourselves if we wanted.

So no, i do not think OC's are 'overriding the place' :]