The possible changes if bitcoin will be legalized are:
1. The government would possibly create a law covering the operation of bitcoin.
2. Investors will be taxed especially those with higher investor value depending on the scheme/bracket or tariff to be created by the bureau
3. Foreign exchange is not be left out like in payment and other transactions will might be given rules and regulations by the Central bank
4. Income of investors will be monitored by the government agency
The government will find way to protect the asset of the people as it is always mentioned when it is not regulated bitcoin could be used in fraud or other illegal activities.