In my personal veiws government would want to have control over bitcoins ,
And maybe they won't legalise BTC untill they get  some power to control it.
Government would surely need to put tax on BTC if the majority uses it , if they form any rules and regulations for using btc we would definitely have to follow it.
What impact it would create on people that we will know only after implementing them .
 
If we talk about current situation then countries like Russia and China have sort of ban on BTC , the ban is not on using btc but to converting them I to fiats by depositing them in banks .