Who is to say Bane wasn't an actual liberator though? For my money, they saw themselves as liberating the entire world by showing how vulnerable a society based on greed and capitalism can be and how it's possible to take it down. The nuke going off would have been one final and shocking cautionary lesson to the whole world.
One just needs to think of what the global ramifications would be if, say New York, had been under siege by a terrorist group for 5 months and then blown to hell.
I think their actual plan was more terrifying than a simple revolution. Oh and by the way, a "simple revolution" would have been impossible to accomplish in Gotham without something like a nuke to deter the government from interfering. And once you bring a nuke into the equation, it's no longer a simple revolution, regardless of whether you intend to detonate it. The threat of nuclear annihilation keeps the majority of people who might want to start an uprising against Bane (IE the middle class) in fear and hiding.