comment and you'll actually find it contains character development, and expansive multi-threaded plot with a greater focus on intrigue, and an elaborate cast of unique characters.
It IS, however, a signifigant departure from the established first two seasons in several ways: The plotline is broad and subtle at first, rather having a more concise narative line, which makes it seems to wander a bit at first. Also the pacing of StrikerS as a 26 ep season versus Nanoha and A's as 13 ep, with a much greater focus on expanded character interaction means that it doesn't have A's silky-smooth upward arc of Tension, or the dramatic change of pace jump that the first season had. It feels very different from either of the first two seasons.
A's is deffinitely best out of the three seasons, but StrikerS is still excellent fare.