The forum thread dealing with the deletion of player theories has been open for discussion for several weeks. In that time, there has been no major outpouring of support for keeping the theories. However, there was a suggestion that was ultimately approved of, which would result in the creation of a forum specifically for player theories.
A few changes are being adopted as a result of that discussion. One, currently-existing player theories pages will be locked down and temporarily archived. This is done to allow any authors who have written theories to relocate them from those pages. After a few weeks, these old theories pages may be deleted. If you do not think the old pages should be deleted, please go here and speak up.
Second, a brand-new forum for player theories has been created - Forum:Player theories. The new forum focuses on discussion of individual theories, rather than simply listing them out on a page. There will be an explanation thread written shortly which will explain how the new forum functions. The forum itself is open right now, so go ahead and contribute!
As always, pay attention to the community discussions forum and the weekly news blogs for any updates on the Player Theories issue.