Anime represents a differing method of entertainment, you look upon anime from the view of one who has lived thier entire life under western culture and hence judge anime by western virtues. So lets open with the anime's you named.
Naruto:
Alright, the orange jumpsuit bit is pretty retarded, I don't dispute that, the outfits are garish and overwrought, made to appeal to the "coolness" factor rather than actual usability. Now aesthetics aside naruto, like most anime, is commenting on a vast and complex topic, like a dissertation stretched out over 90 episode (I don't count the filler bullshit). Shippuden, which is naruto after a two year time-skip, continues to speak on the same topic in greater detail. Namely the top is about generations, the young taking over for the old, the sins of the fathers haunting the sons and daughters. Each character has his or her own parallel, Naruto is the parallel of Jiraiya, the cocky and powerful sage haunted by his past failures and mistakes. Sasuke is paralleled by Kakashi, a prodigal ninja with great power and constantly driven by the violent deaths of loved ones.
The list goes on, Anime tells stories of epic scope in most cases, I will say that plenty of anime are just childs play, but they are cartoons, they have the right to be that if they want.
Code Geass:
From your posting I realize I have very little to explain here, the simple fact is that you didn't understand the plot and what was happening, you can say that its too convoluted but the fact is that I and many others followed it just fine. It's a complicated story that functions on a constant image of social Darwinism, betrayals and alliances, the almost ridiculous but accurate requirements for obeying rules of politic and propriety. If you didn't understand it then, well, not much I can do there.
Tengen Toppa Gurren Lagann:
This anime focused heavily on well-developed characters, I don't know where in the series you got dropped into but I will concede that this is a story that you have to read from the beginning. As an anime it told a story of driving will and dreams, and while that may sound childish the fact is that progress is built on dreams. The wild imaginings of today are the everyday accepted facts of tomorrow, just look at Star Trek. Gurren Lagann begins in a village that is one of many, holed up underground, life is dreary and gray, an analog of a world without dreams, where no one cares to imagine anything different. The story starts as it means to go on by creating a world of analogs, characters each representing something different, peace, drive, will, determination, despair, violence, acceptance.
So whether you're willing to see these things or if you're unable to accept that anything animated could possibly have a message worth listening to, I don't really care, but referring to Anime as an "artistic train wreck" only shows the narrow mind of someone who will never be able to create anything truly grand. I don't care to convince you of anything, but I would thank you not to speak on subjects you have absolutely no knowledge of just because it isn't to your taste.
Also I apologize for the length, if I go any further its going to resemble proust's a la recherche du temps perdu.