I think that the balance has a lot to do with the DM. Place at least three combat encounters in a session to wear out the magic users or provide enough opportunities so the rogue can shine, yes the rogue class is not going to be as enjoyable to play as nonrogue classes if those things are not...
I hope that there are some Fourth edition versions of OGL games out currently as I would buy at least one copy to show support for the company of my favored game line.
I was going to reply with a sarcastic comment about not having seen them but ban them anyway because I would assume they suck/overpowered. Though I will see if that is so first.
I have noticed a lack of artwork/maps that are OGC so I wanted to fix that by creating and releasing some artwork and/or maps for people to use. I may be incorrect but there isn't hardly any.
I could see where you're coming from although what other really major event could they announce it at? It's been eight years since the last edition came out so maybe they wanted to follow with what they did last time?
I first heard of Mike Mearls (IIRC) when I bought Iron Heroes after reading the back cover of that book, I took a chance and I was not disappointed. I am happy I did too!
I'd say Mearls.