I think that regulation is something that is inevitable and more and more countries will decide to regulate Bitcoin in some way. But I don't think that regulation is equal to centralization. Bitcoin can be regulated and decentralized at the same time.
Regulation means seting some rules how Bitcoin should be treated, what is legal and what isn't, how it should be fitted into financial framework.
I think that regulation could strengthen Bitcoin and help it to be more accepted, we don't have to be afraid of that.
Regulations are set by a central authority without the approval of another parts involved on the situation (Bitcoin enthusiasts). Banks and governments create the rules they want and impose it to you. And with rules the taxes come together... By dealing with Crypto-Currency you will be just working for the government (that doesn't share the risk when you are investing on this volatile market, but wants a peice of the final profit). I think it's very centralized.
But indeed it's inevitable...
Feel free to create a union of Bitcoin enthusiasts that will hire some good lawyers and economists (honestly crypto society is lacking of them), make some summits where you will invite government authorities and bankers, discuss the situation around cryptocurrencies and how it can work in current society, then prepare a project of the healthy crypto regulation and push it to the government. Then it will be approved by both sides. Does it sound too hard? Unfortunately I haven't see a strong will to do something like that. Both sides only scream that everything is bad.