Finally, an article that I can get behind.
My favorite campaign setting for 2nd Edition was Planescape, hands down. I loved the look and feel, and the fact that you could journey to exotic and alien worlds without having to be high-level. Sure, many were extremely hostile even if you were high level, but it opened up a lot of possibilities at the start of a campaign. Aside from the Nine Hells and Mount Celestia, there was a world that was like a sandwich (Bytopia, if I recall) and another that was a vast open space with metallic cubes crashing into eachother (along with storms of razor blades).
Still more bizarre however, was Mechanus: a space of gears and cogs constantly grinding and turning for an unknown purpose, though there were several theories, such that if they stopped that the Multiverse would end. In 2nd Edition, this place was inhabited by modrons, equally bizarre creatures whose lesser incarnations adopted the shapes of geometric solids, such as spheres and cubes. Others, well, didn't, such as the tridrone, which looked like a starfish with a one-eyed face on each arm, walking on five legs.
The article goes over some brief descriptions, such as that monodrones are spherical, and both duodrones and quadrones are like cubes, which in unfortunate because I think that a picture best delivers their alien appearance. There's a lot more than that, but it serves for the purpose of the article.
One thing that I like a lot about the new modrons is that they are pieced together from lesser ones. Before, each type had a specific number. When a ranking modron died, lesser forms were promoted and created as necessary to fill the gap, ensuring a static number of modrons Now, it seems that lesser ranking modrons combine in order to, ahem, transform into the next rank, and dissemble into lesser ranking modrons when killed: in combat, every modron except for a monodrone separates into others that keep the fight going.
I also like their new niche: searching for planar rifts and either protecting them or sealing them. In this way, they help create stability across the planes, which is a far cry more direct that whatever nebulous purpose they had before. Honestly? If there was one aside from maintaining Mechanus, I don't recall it. This seems as a fairly easy way to throw them at the players, especially if they are trying to find a way into the Shadowfell or Feywild.
The only thing the article is missing is a racial writeup for rogue modrons. How would you do it?