I loved how the show left it open for a new season, or mini-series, or whatever format by sending Kellog to the past. Because there, being Kellog, all he has to do is pull out his cell phone, convince the Native Americans he is a god, reunite the tribes under his rule in North America, and tilt the balance of power against the incoming Europeans, doing irreparable damage to the timeline in the process.
Future 2077 Alec or the Time Traveler/time cops would then be compelled to send Kiera, Garza, and/or Carlos to restore the time line ... However, as much as they hate Kellog and his changing history by creating a North American empire of indigenous tribes, they also don't care for the original history of their genocide at the hands of Europeans. We will then see a lot of tension, infighting, double-crosses around that issue among the group of would-be timeline restorers.
Of course the primary purpose of such a storyline is to serve as a pretext to get Kiera into a 17th-century corset.