So Lightning. It's described in the Guide to the Inner Planes as being a stormy plane. Billowing clouds that light up from the inside, peals of thunder rolling across the entire plane, gale force winds blowing every direction and lots and lots of lightning. Much like Air, Smoke or Steam, there's virtually no solid ground in this place. If it weren't for the risk of getting continually jolted by lightning strikes, it sounds like the plane would be almost as hospitable as Air.
In considering Ooze, it was relatively easy to hit on an overarching theme/concept for it (Growth vs. Decay). Lightning is a bit more difficult, but my thoughts run along the lines of there being an Intensity vs. Calmness mood in the place, but nothing really comes out of that.
I suppose the best approach to take would be to consider why non-natives would go to the plane. Or, failing anything readily apparent on that front, how they would get by long enough to want to call the place home. For a non-native to survive for any length of time, they would need two things (at least from my perspective): some means of dealing with lightning strikes and some way to keep from blowing away when a strong gale hits. I see there being pockets of relative calm amongst the storms, akin to the eye of a hurricane. A calm center with raging wall of stormy clouds all about.
Ok, I need to think on this some more. But maybe there's something here that can spark somebody else's ideas (pun unintended, but still awesome).
I'd imagine that among the non-natives of the plane, there's a bunch there as Lightning-Riders. Maybe they like the thrills, or are trying to utilize technology similar to the Elemental Bound Airships of House Lyrandar or House Orien's Lightning Rail.