Change in government - it's simply means when another government enter there's will be reduction or addition of some policies.
Applies to all economic sectors. Why bitcoin only? As a matter of fact, use of bitcoin on a country basis is still small and so the policy affecting bitcoin would be small too. Moreover, government leaders dont change policies immediately, they do some cost-benefit check before changing them.
Political instability - when political system in the country is not stable, everything will get down.
Yeah the electricity will also go down making bitcoin useless. Are we talking about absolutes or variables?
The biggest factor is neither of the above, it is Demand/supple ratio. If people want to do shopping with bitcoin, a bitcoin based business will flourish, because the government is not controlling bitcoin, though it would help a lot of they make it legal.