I'm not too concerned about countries making Bitcoin their legal tender, I don't think that Bitcoin is meant to be in control of any centralized authority, it is meant to be in the control of individuals and perhaps institutions. If the adoption of Bitcoin will increase to the extent that everybody is making use of it as an alternative currency for p2p transactions, that will be better for me. It will be a boost no doubt if big countries like China and India, were to adopt Bitcoin as a legal tender, although I don't see it happening, it'll boost Bitcoin adoption and it's price will surely increase. But I am more concerned for the whole countries in the world to be Bitcoin friendly, not having any restrictions for it's transactions.