When I started watching Stargate Atlantis, I was only mildly interested. After all, space vampires as the big bad of the series were hard to take seriously. I have no trouble with space vampires in trash science fiction, but Stargate always tried to play it straight and I hoped the spin-off would be at least as serious. But while the space vampires, their origin and their abilities were always a bit wonky in terms of convincing sciency bits, what I really liked was how the series played them. Most vampire fiction never ventures into the scenario of what happens when you have more vampires than food supply.
Sure, there was Daybreakers (interesting concept, disappointing execution), but rarely do we see the outcome of a successful taking over of the world by the vampires. In Stargate Atlantis they didn’t just take over the world, they took over the galaxy. Their lifecycle was perfectly integrated with the population growth of the human worlds and the population of the entire galaxy. Once too many people had been culled from all over the galaxy, most of the vampires went into eons long sleep mode. Also most of the vampire clans in their hive ships woke up in shift, so not to overextend the burden of culling the sheep and destroying their feeding grounds.
Into that finely tuned systems the humans came like the proverbial wrench in the machine, waking up all the hives at once. While initially united against the Earth humans, soon they fell on each on other due to limited feeding resources in their galaxy. It really was something of a beauty to behold to see how the whole too much vampires to feed scenario played out.
Not to say that Stargate Atlantis was perfect. They killed of one of the best characters the show had (Elizabeth Weir, man she was the perfect leader for the Atlantis expedition), replaced here with Samantha Carter whose actress turned in a relatively bland performance (probably due to the writers of the show again not knowing what to do with a female leader) and then replaced her with IOA mainstay Richard Woolsey, who I really hated and yet who the writers wanted to portray positively (which did not work at all, he was an incompetent control freak from start to finish).
Really, the show could have been easily called the John Sheppard and Rodney McKay show, as those two were the center piece and everyone else just patchwork. Teyla was the token female who was never allowed to play much of a role (and that diminished even moreso as the series went on), Ronan never ventured far beyond being the simple warrior archetype and most of the characters were just as sketchy. And while it was nice to see McKey go from complete asshole to an asshole with a human side, it wasn’t exactly a character arc I haven’t seen on countless other shows and the same applied even more to John Sheppard.
Apart from the space vampires and their generic fantasy/heavy metal look the series provided a substitute replicator race which lacked the cool visual design of the originals and a local human culture who sometimes played the antagonist (the Genii). What was interesting, though not in positive way, was how the Atlantis expedition was the perfect metaphor for western imperialism, completely forgoing local cultures and terming their efforts to fight the space vampires as weak sauce with only Earth humans doing it the right way. The original series had similar elements, but in Atlantis it was ten times as wrong and neither the characters nor the creators of the series ever acknowledged that this was even a problem. Totally oblivious and clueless.
Plotwise the best stuff happened in the first three seasons with a few good episodes in the fourth and even the last series. Overall though, the seasons went from good (never great) for the first three to mediocre (fourth season) to disappointing and often boring (last season) with an ending that was a whimper compared to a few of the best episodes like the ending of the replicator threat. They tried for something epic with a final conflict converging on Earth, but it definitely was not the well-placed and -played climax to the long-running conflict with the space vampires (I love saying that). Very similar in approach and execution to the last episode of Star Trek Voyager, which equally went out with a whimper, where after it you felt like This is it? Really, are you fucking with me?!?.