my mind always asks, if one day bitcoin gets legal regulation, and is recognized all over the world. ...
But why would you rely on regulations so much? Why it's so important for you, that some political body will give you special permission to use bitcoin? You and everybody else, can use it, even when stupid politician says otherwise..
~snip~
Exactly that's the point. Bitcoin was made to give freedom to public, if we rely on government authorities than the purpose of bitcoin will no longer exists.
Regulation may be encourage global adoption but it will take away the financial freedom for which bitcoin was designed.
Moreover a single currency for the whole world seems unrealistic and will not going to happen.