My main complaint with Reddit is that the direction it's been taking the site over the past five years or so, and more pointedly the improvements it's not made, are far divorced from where I'd like to see it go.
Reddit wastes my time and does not reward time spent on site with valuable insights. Not strictly for cultivating misinformation and disinformation, though that's a fair-sized piece of my concern. I'm more concerned that it simply kills good conversation or prevents it from arising in the first place.