Nope. Something is only pretentious if it DOESN'T have substance or story but alludes to having one.>>10596326
Now you're making me lol. Go ahead, criticize the FMA anime OR manga. I won't stop you.
And yes seinen is good, but you'd have to be a fool to think that's the only genre. Some of the best series are shounen (GTO, Kenshin, Detective Conan) and these definitely should be mandatory before you dismiss shounen. And there are some good shoujo, like Aishiteruze Baby with rather mature subject matters.