Yeah, that's another possibility - focus on a Federation colony under attack by mysterious aliens. You could have family groups and Starfleet characters, and have some episodes still set in space (the attack could be against a group of colonized worlds or there's a nearby Starbase etc.)
That idea could be merged with The Walking Dead. Either way, it would be good for basic cable. The distinction would be the amount of violence allowed. On TNT or USA (or even SyFy?), less violence while on AMC or FX, more.