Here's a premise that just occured to me.
The show has largely been about our past (mythological gods, ancient artifacts, etc). Sending an archeologist into space was a twist, because space was about the future.
As the show went on we mastered technologies, established outposts, and pretty much conquered the galaxy, kind of killing the original premise along the way. What will mankind have done next?
Reveal the Stargate program to the public, expand and settle onto countless alien worlds, build starships and giant space habitats. We maintain a population growth rate of 2% because we never hit the limits imposed by living on a single planet, so in 300 years the human population is 2.7 trillion, with about 400 planets as heavily populated as Earth is today. Our cultures blend and merge and incorporate small influences from the primitive human settlements that had been spread by the Goa'uld. Violence becomes almost unheard of, and people fully expect to live 200 or 300 years using advanced Ancient and Asgard medical advances, along with our own.
**** pitch ****
And then one day in 2325 AD, a couple of SG teams from the year 2014 step out of a stargate, their homeward jump path having gone through a solar flare. The local Earth government realizes the arrivals are from some of the famous SG teams that had mysteriously vanished centuries earlier, but who had already made humanity's final expansion possible. Perhaps the elite SGC relics from the past can fix some serious problems that the stayed-at-home, soft, self-indulged, unmotivated, tenth generation, virtual reality-addicted couch potatoes can't.
Every planet will still look like British Columbia, but now they'll include Vancouver and its suburbs. Instead of creating Asgard, Goa'uld, Ancient, and alien sets, most of the show will be filmed on regular streets, malls, parks, and houses. Instead of dreaming up different primitive versions of human cultures, it will be about future versions of human cultures, extrapolating from current trends or drawing from a host of sci-fi novels, but we'll get to see the future from the perspective of our familiar SG teams who are, along with us, trying to relate to these new cultures and the future.
The show will look and feel vastly different from SG-1, SGA, and SGU. Perhaps it will be a bit more like "Fringe", but with the added element of hundreds of future Earths, and far future ones, not just two parallel ones in our near term. On most of these other planets we settled, the humans will have recreated a look quite similar to *cough* Vancouver, or LA.
By anchoring the premise on the Stargate, it lets you write almost any futuristic story arc for Earth's future ("Blade Runner", "Running Man", "Drudge Dread", "Fringe", and countless others) and then just stick the particular storyline on one of the planets we settle, so you can get a long-running series from individual sci-fi stories that would only hold up for a half season or less. And you always have the possibility of aliens, galactic invasions, and whatnot (the old story arcs) with most humans on most planets being too self-absorbed to really care.
I'll call this one "Stargate - Futures"