Yeah as anime any shonen is crap most of the time, they also have fillers all over it. The character develoment is bad, the story isn't too interesting because at some point you will lose interest even if the original concept was good, either that or they really managed it badly.
ie bleach has great characters, but there's so many there's barely any character development, the conflicts are blindly resolved through violence and hardly any good guy dies. The original shinigami idea is p cool but I mean 300 chapters in it gets old. it really goes downhill as time goes on, it's entertaining somewhat, but not as good. Last arc on the manga is actually not bad which is a shame if it doesn't get animated. But that's no excuse if 200+ chapters weren't great.
From what I've heard Fairy tail suffers from most of these traits, plus a way more annoying protagonist if you ask me. good art unlike bleach but terrible characters and character development, storyless basically because characters barely keep track of their goals, etc.
Like I already said, p much everyone I know says Hunter X Hunter is the pinnacle of shounen. It has good art, good storyline and good characters and they're all managed great during the series. It has somewhat of a slow start but that's about the only bad thing I've heard about it and it isn't even bad.