I strongly disagree with that idea. The moment you see a regulation of who gets to post new valid blocks is a big red warning sign.
Correct, it does raise a dangerous precedent.
You simply can't regulate this market, it's global and anonnymous, you don't know who is mining and where he is.
Yes and no.
If we assume Bitcoin is behind the world's financial system then I can certainly envision a scenario where governments would want to use force to prevent some mining installations from approaching uncomfortable hashing %.
Considering the advent of mining farms it certainly is possible to find out where the operations are located. This is not someone mining on his computer anymore.
Of course this is all speculation. If Bitcoin achieves global reserve status then it is fair to question whether governments will have much power at all.