The reason you think AOT is overrated is exactly because you haven't read the manga. The anime is very good to begin wtih, I mean animation and artwork are excellent, however, none of these is a decisive factor. The reason for which AOT is unique is because of its plot and characters, who are far more humane than any other manga I have read. What really keeps me interested is characters' development the way it's depicted in the manga, in the anime it wasn't that much touched. In any case, if you do read the manga eventually, you'll see that the plot is way more complicated and philosophical in a way that greatly surpasses what it looks like at first as just "humans vs titans".