I take issue with your premise: NO BIG GAMES (with the exception of Portal 2 and Starcraft 2) have been released for Mac this far.)
Evidently, you're unfamiliar with Steam. I don't know what your definition of "big games" is, but in my mind Civilization V, Counter-Strike, Assassin's Creed 2, etc. qualify. Best part about Steam is that if you buy a game, you can download it for Windows and/or Macintosh.
Yes, if you want to play Windows PC games the best option is to use Boot Camp. And yes, you have to buy Windows to install in Boot Camp. Of course, if you were to purchase a Windows PC you would also have to buy Windows.
So, I'm not sure what you expect here… Apple should throw in a copy of Windows for free? Apple should spend money and resources to incorporate Wine or Cider into the OS and go through the tremendous support and legal headache while simultaneously cutting its developers off at the knees by allowing Windows applications to flood the ecosystem? — not that it would ever happen… ;)
Apple's last OS update, 10.6 was a $30 upgrade. 10.7 Lion will also be a $30 upgrade. Seems to me your beef should be with Microsoft's pricing of Windows. (Oh, and lazy/cheap game developers of course. heh.)
To answer the central question: Wine and Cider are both legal, since they use no code or binary data from Microsoft's implementation of Windows.
Yes. Excluding any major issues, the GM release for developers is the same as the first release to the public. Future point releases can be updated over-the-air rather than through a manual image install.
Best Answer
Since Lion, the developer program issues its beta seeds of the OS using the Mac App Store. You get a code in the developer portal which is redeemed in the Mac App Store. You can redeem this code on any Apple ID. It does NOT need to be the Apple ID that you signed up with on the dev portal. Once the final release is out, the beta seed in your App Store is transformed into the fully released version.
So yes, you do get it. And in fact, you will be unable to purchase it on the Apple ID with which you redeemed the seed.