I wouldn't be able to comment on whether it is hard to follow because it's really complex or if it is because it's a complete mess. I can tell that the people voting on anime news network haven't been terribly impressed with it and that the ones writing about it on tvtropes seem to be part of the manga. If I were to guess, however, I'd imagine that part of the problem is that it's a 2002 adaptation of a manga that ended in 2006, meaning that a whole lot of stuff probably went unexplained. Especially as it appears it isn't a terribly competent adaptation of a story with a very large cast.

Still, even that doesn't help me much in determining what to recommend. What I can tell is that you seem to favor action, though that might just be a question of exposure, so I guess I'll concentrate recommendations in that area.

If you're fine with mecha Full Metal Panic! is a really good show with fairly good action both on foot and in mecha as well as a strong cast and some of the best comedy in anime, especially in the second season. Especially the dynamic between the main characters, Sousuke and Kaname, is great, with the added conflict presented by Sousuke's less than professional superior. The villain can be divisive, though. Some people consider him a great, scary and intimidating villain, some too over the top and ridiculous and some are just disgusted by him and think the show lets him off too easily.

If you can find it, which is fairly easy if you're willing to buy an expensive Blu-Ray release and very hard otherwise, Read or Die is quite amazing too. The ova, which is the first part of the story, is enjoyable, fast-paced pulp action with some of the best animated, fastest fight scenes I've seen in anime and clever use of one of the coolest superpowers ever. The tv series lowers the animation quality slightly, in favor of a plot that actually tries to be coherent and one of the strongest casts of any action anything ever. Some people expecting constant action are put off by the slow start, though, which is a shame since it has a lot of cool action and a very tense feel later and the slow start has excellent character development.

You might be interested in Baccano! too. A crazy, fast-paced story about immortal gangsters trying to kill each other, with a host of insane and over the top characters who tend to be fun despite largely being horrible people. Lots of incredibly cool action, hilarious ramblings and catchy, jazzy music. Hard to really say that much about it since it's mostly about style, which it does extremely well.

Finally there is the eternal recommendation that always crops up, Cowboy Bebop. Probably the show most renowned for its dub ever, with great music and what might well be the best animation of any 90s tv series. It's also accessible and has an episodic format that works thanks to the strength of the writing and the vision of the setting and the characters and is generally quite deserving of its status as a classic.