I think it would be... oddd...behaviour of someone to use WotC's work to freely create stuff and
then try to establish restrictons on what they've created. In my eyes, that would be the height of hypocrisy.
Tracts of fluff text, of course is another matter - but mechanical stuff, like classes, feats, powers... it's completely derivative of 4E (it would have to be, or it wouldn't work with it); and in mnay cases, very derivative of 3E, even 2E or 1E.
Added to that - putting it in the Wiki (still on EN World) is no different to a moderator copying or moving a thread, or me putting it in the news.
Hmm.. that's a good point. My Fan Creation of the Week item - I'm going to select it from the Wiki only from now on. I think if you're happy to have it on the front page, you can hardly object to it being in the Wiki. So, if you want to be considered - copy and paste that sucker!
In truth, the chances of someone objecting to their stuff being put in the Wiki is pretty unlikely. We're putting it here to share it, right?