I have unfollowed about 200 people I used to follow because they were dead wood. Hadn't voted or posted in over 6 months. Now I know a lot of people that are followers are dead wood too, but I still haven't found a way to cull them from my feed. You are right when you talk about resteemed posts. I literally have 100's of those every day as well as bots, and spammers. It takes the fun out of trying to engage meaningfully. I am not sure what the answers are, perhaps someone more tech-savvy than me can come up with a solution.