If it is considered 'united' with Ukraine and they retain autonomy, why wasn't it left as is?
Not sure I fully understand the question. Anyway, the choice will be between the original broader autonomy within Ukraine and joining Russia. Why? Because the “status quo” is designed by Kiev and never by locals, and it's unacceptable at the moment. They don't even want to consider it deserving voting.))

I bet you can easily predict the result of the referendum, btw.