I think that no matter who you are and how big you are (Facebook) you have to come out clean.

If you say that every developer has the same deal going on, no matter how much money they pump in, you should give them the same tools. If you DO think that who performs better should get better deals, as every business would, then just say so.

Playing the way they played so far (giving poor support, shutting down apps, making subtle deals, etc) do Facebook think they can really leverage developers with the HTML5 platform when they release it?

The only reason why developers want to keep working on Facebook is for their (official) userbase. Facebook knows that and they didn't do anything better than showing muscles so far.