Hell, some UK series are only 12 episodes. Shows here tend to either run until it's pure soap, or get killed before it even gets a chance to get off the ground. Watching MI-5, it's also refreshing to see pure focus on scenarios, and not on individual characters. Keeps it fresh and unpredictable.
Swedish crime dramas at least used to be short run as well, more like miniseries than standard TV series, with higher production values, better pacing and more content in each episode.