I sympathize 100% with Iranians who want the regime gone and sympathize 0% with any figure of the current regime, including Musavi.
He is a tool... in both senses. Until now he was a tool of the regime, but has been turned to be a tool to crack up the very regime he was part of.
Quite an irony, actually.
It’s just conceivable that if the current government were overthrown and Musavi were installed in its place, he would change his political approach because he needed to rely on the good will of the people who put him into power.
That means too unlikely events: overturning the government, and getting some sort of decent behavior out of Mousavi. But it’s at least possible.
But it’s noticeable that the demonstrators on both sides are yelling “Allahu Akhbar” as they demonstrate or shoot demonstraors. Yet they mean something different by it, though the words are the same. Iran would still be an Islamic republic, but it could be a lot less of a troublemaker in the world than it is now.
The odds are highly against it. But no harm in hoping.