I don't think a TV show needs a central mystery. It can certainly be a fun structure, but it isn't the only way to do good genre television. Yet for some reason JJ Abrams keeps being attracted to that format, and the latest show with his name on it - NBC's Revolution, co-created with Supernatural's Eric Kripke - ends up having a big central mystery.
Revolution's central concept is that 15 years ago all electricity stopped working. Now the nation has become a semi-post-apocalyptic place where warlords rule and people are forced to shoot one another with crossbows and grow gardens in their car engine blocks. I think that concept - the world after a horrible energy crisis - is good enough. But Revolution has another layer: something caused the (frankly illogical) end of electricity... and some people seem to still have access to it. Which they use to power the computer from The Hatch on Lost.
I don't know that I care about the mystery. Just tell me a good story about surviving in this new world. I'll give the show a chance because I like Billy Burke as a New Dark Ages badass, but I suspect this thing is going to get silly quickly.