You won't find anyone here who could be considered a 'professional game designer', I don't think-- there are some game designer designers
, and a few people loosely tied in to the industry, and some great indie developers, but nobody who's really inside what's going on in the dev scene.
What I'd suggest is actually trying to make a video-- sign up on Gamasutra, they might have some videos about game design, and they have some video interviews. Perhaps you could mix them and intersperse the final video with snippits from an article based on what you read in some of the game post-mortems and developer interviews there?