Arab regimes (and Iran) often warn against change and revolutions: they try to scare us by warning of the potential for chaos. I say: we should work for the overthrow of all those regimes (Arab regimes and Iran) because chaos is far superior to those regime. At least, under chaos there is a stronger chance for change and sabotage (sabotage of oppression and injustice and occupation and conspiracies).But I doubt that most leftists in the oppositions in Iran and the Arab world are looking for "chaos." In any case, they are too few in number and too unorganized to take advantage of it if that's the idea. Instead, such leftists as exist there are looking to establish better governments than they have and wish to lead organized mass action for that purpose, though in most cases they end up following rather than leading rebellious largely-non-left-wing crowds when such arise.
If you want chaos, you can find it in Somalia, for instance, and increasingly in Libya as well, but Libya and Somalia (unlike Egypt and Tunisia), if anything, are in all likelihood disincentives, not incentives, for would-be left-wing revolutionaries elsewhere.