Actually, we have a rise of a peaceful alternative to Zardari. His name is Imran Khan. He's the leader of PTI, Pakistan's movement for justice party.
And, as for your analogy of Zaradri, yes he has killed millions by being a jackass, but Assad is deliberatively ordering his troops to go out to kill and torture innocent protesters who want him out.
Zardari can't really do anything like that to us, we protest everyday, we attack police officers on a even scale, we even set out PM to jail for a minute (mind you, most countries don't have the guts to do this).
So, you can't compare the situation of poverty in Pakistan, to the deliberate actions of the tyrant Assad.
I do realize that America, China, Russia, the European Union, and Israel want him in or out for their own reasons.