Tried to find the WC 3 specific forum, but I guess it wasn't up yet. I just need to know if Wing Commander 3 is compatible with a gamepad. If it isn't, is a keyboard & mouse good enough for those who don't have a joystick?

I believe the Wing Commander 1-3 questions can be fielded in the Wing Commander Privateer forum ... GOG just needs to rename it to the Wing Commander Series forum like the forums for other game series on GOG (except for the Witcher 2 which has its own forum and is obviously a special case). Unfortunately I can't actually answer the real thing you wanted to know. It's on my wishlist. :)