Revolution is no good as an aim in and of itself.  Just look at the disastrous results of "revolutions" in Mexico and Cuba . . . and soon to be Venezuela.  How are those revolutions of the proletariat in Africa working out?

I think any real progress we make comes in slow, almost imperceptible steps.  The cliche is one of two steps forward and one step back (sometimes two or three steps back).  Only when we get 100-200 years away can we see a more defined arc. 

We might debate this, but I think you can pretty clearly show an arc toward greater freedom worldwide over the past 200-300 years.  We just happen to be backsliding at the moment.