Carnivale, as you may recall, completely bowled me over with the first season. It improved on what the first season of Babylon 5 set out to do: using a series of apparently-separate stories to set the scene for a much larger one, while establishing the tone for the rest of the series. By turns whisper-quiet and shouting from behind you, it was the best opening to a series I've seen.
From there, it was perhaps inevitable that season 2 would be a bit of a letdown. It's still *quite* strong, mind, but it's B+ work next to the grade-A first season. Mostly, it suffers from having to actually get on and *tell* the story it has been setting up for so long. By mid-season, most of the major mysteries have been unveiled, and it doesn't introduce a lot of new ones. So whereas the first season is entirely about tone, this one is more dominated by a plot that begins careening forward relatively quickly.
Really, the odd thing is that the pacing changes dramatically in the second season. The first season's pacing is very slow and deliberate, which works well to establish the creepy tone. The second, especially the latter half of the second, moves rapidly towards the climax. Indeed, it moves *so* rapidly towards the climax that msmemory and I were near-certain that they were going to end the story there -- they'd cleared up enough mysteries, and were so obviously building towards the operatic end, that we figured that was it. There were a few threads left hanging, but I'd figured they were minor inconsistencies.
In the end, the story did *not* end, and that is in and of itself a new mystery -- I honestly have no idea where they're going from here. I'll avoid spoilers save to say that the end of season 2 is far less of a cliffhanger than season 1, but quietly much darker. I suspect that the story gets quite a bit grimmer from here, but we shall see. (Assuming they continue the series, which I hope they do.)
Overall: still my favorite current series. Quiet horror, with an edge of grand guignol that shows just occasionally. It doesn't appear to have quite as intensely-designed an arc as B5, but far moreso than almost anything else: it is rich in foreshadowing. Usually very well-written, although better in the quieter stretches. Thumbs up, with fingers crossed that it continues and returns to the style of the subtler first season.
Stargate SG-1 has been a background favorite of mine for many years. I usually refer to it as the true successor to the original Star Trek series, in which our heroes travel to strange new worlds, meet alien races, rescue the good guys and blow up the bad guys. Fairly average science fiction -- not particularly good science, but decently consistent and logical. Never really deep, but always fun and generally well-crafted.
However, there was an inflection point in Season 8 when that last clause seemed to have finally ended. After a fairly decent season, they hit a totally strange section near the end. For one scary moment, I was absolutely certain that the series had jumped the shark.
In a massive three-parter, they decided to change *everything* about the series. In one long story, they: killed off one of the main recurring characters; eliminated *most* of the established bad guys of the series; rewound the romantic tension by about four seasons; "resolved" the Organian-style "ascension" storyline by establishing that it was all just a mistake; and ended the Jaffa plot that has been running since the first episode of the series. It felt like they had handed the series to some fanboy, and told him, "You have three hours to make your mark on this series. Have fun." *Terrible* stuff -- not even good fanfic-level, and apparently demolishing years' worth of story-building.
That said, the rest of the season was right back to the usual good quality, ending with a time-travel shaggy dog story so ornately silly it was worthy of Next Gen. My best guess is that the writers simply decided that they were in a rut, and chose to hit the series with a continuity-clearing tidal wave, getting all the pain out of the way quickly so they could get back to writing what they wanted, focused more on the people and less on the plot.
Overall, I'll give the season a B-: that's a B for most of it, reduced by the C- trilogy in the middle. I haven't heard yet whether it's being picked up for another season, but it still seems worth watching, although not a must-see.
MI-5 (known in Britain as Spooks) is the kind of series that they just don't make in the US. It is an unsparing, depressing look at life as a spy. There have been three half-size seasons (this is a British series, remember), each one darker than the one before it.
Season 3 pulls out all the stops, dealing brutally with issues of loyalty, love and death, and demonstrating that there are no sacred cows in this story. I mean, the season starts with Tom (ostensibly the protagonist of the story to date) being framed for treason and leaving the series. From there on -- well, I think of this season as "The Descent of Danny Hunter". Danny was the youngest of the original main characters, and the only one who really retained much idealism. He serves as the emotional core of this season, as he slowly realizes that his job doesn't have much room for idealism or idealists.
The season, and indeed the series as a whole, is a solid B+ for me. I doubt it's entirely realistic, but it's a consistently gripping thriller. It is *never* fun, but it has a deep angst that consistently engages me. Building on the rapport we've built up with these characters, this season lacerates us by tearing those characters apart, more honestly than you'll usually find star-driven American TV willing to do. If you enjoy well-written pain, I recommend it.