Yeah, I'm aware of that: I had a whole fucking school term devoted to this turd. That still doesn't make the book any less laborious to read - its especially awkward now as language has drifted so some of the prose simply reads in ways that make it sound funny to a modern audience. Also as has been ably stated elsewhere that deliberately annoying (or reprehensible) is still annoying.Except the entire point of Great Gatsby is that it's condemning everything you've described. You're not really meant to find any of the characters sympathetic bar Nick and arguably Gatsby (James Gatz) himself.
Like I've said before, I'm not the smartest guy in the room so maybe a shitload of the nuance and cleverness of the novel is lost on me but if I don't give a shit about anyone, then all that clever writing is for nought because all I'm going to do is put Gatsby down and go pick up The Power of One again.