When we talk about legalization of cryptocurrencies across the world, it is yet to be confirmed that all countries will be able to adapt to its usage. All of them have their own issues in regards to the currency use. I believe its not possible for cryptocurrency to become completely legalized worldwide, considering its current position in the market.
Only the nations where the governments have the intelligence to understand the benefits of Bitcoin will try to legalize crypto-currency. On the other hand, in the third world nations, the aim of the governments is to enslave the citizens. So we can't expect them to make BTC legal.