I would say yes but only on average because revolutions are made by coalitions of opponents of the regime.
For example, the overthrow of the Shah was achieved through the combined forces of liberals, secular nationalists, conservative Islamists, communists, populist leftist Islamists, etc. Only for one group was it worth it. Likewise in Algeria (where the secular nationalists won), Russia (where the communists won the civil war, and secular nationalists are winning after the fall of communism), etc.
For the group that wins, the revolution can be considered worth it, but many will be disappointed.
Note that I am taking a more subjective approach to this issue than Eugine_Neir did. I think it is fair for an inefficient ramshackle dictatorship to consider their revolution a success if they get to spread their ideology.
On reddit today I read 'the-Gandhi-quote' on a post about the Wall Street Occupation Protest:
"First they ignore you. Then they laugh at you.."
I'm transitioning, possibly, from the laughing stage and am beginning to feel the tiniest bit excited that perhaps some actual change is in order. On the one hand, I feel sufficiently skeptical about the probability of a 'revolution'. On the other hand, given how fast the world has been changing (the internet, gloablization), maybe change is inevitable and this is the way it happens now.
I know this is a rationality site, not a current affairs site, but when something tweaks my interest I like to know what "Less Wrong" thinks...waiting for a spontaneous post could take forever and finding a 'rationality-spin' would be disingenuous so I'll just ask:
What is possible and what is likely?
What factors are important?