In general, games are extremely role-heavy these days. There have been a very large number of mafia games over the last few years (here's the most up-to-date list), and after a while people got bored of getting plain townie roles. As a result, games have gradually become far more role-heavy. This includes multiple mafia families, various third party groups, and all kinds of whacky pro-town roles. However, many games have actively eliminated the 'classic' townie, and instead give every single player at least something small to do beyond voting, or some minor power to keep them more interested in the game. That right there is where a lot of the complexity comes in.

The games that are generally considered to be benchmarks in Org Mafia gaming are Seamus' Capo games. They remain the largest games ever played here, and have levels of complexity that are mind-boggling. Here are the links to Capo I, Capo II, and Capo III. Reading those might help get an understanding for the scale of some of these things, though those are also HUGE threads and will take a very long time to move through. If you do want to read one, I recommend Capo II as the start. I think it's generally regarded as the best of the trilogy, largely because the winning mafia boss started the game as a plain townie.