I liked that it moved away from the murder-of-the-week formula and leaned into the real story of the increasingly imminent zombie apocalypse. It's still a CW show, of course, with all of the limitations that implies. But it scratches the same itch that Battlestar Galactica did, re: "This is the end of the world and we're just pretending to be a civilization." I look forward to the final season, because I genuinely want Liv to have a happy ending.
If I have one complaint, however, it's that there should be more visible effects of the blockade/siege on New Seattle. The U.S. might guarantee shipments of essential supplies to keep the city operating, but there should be shortages of non-essentials and a black market for more than just brains. Also, with Liv, Major, and Peyton pretty much running the city together, when and how will they address the fact that Fillmore-Graves was keeping the population of New Seattle as human shields? Will the humans now be free to leave the city, assuming the U.S. clears them to do so? Or will Major be forced to continue Chase Graves' policies because he was fundamentally right all along?
If the show is smart, that's what the final season will be about. Until Ravi discovers the yes-this-is-finally-it-and-we-can-produce-as-much-as-we-need cure, of course.