Bots are an issue if you try reading replies.I have to say that in general I don't find Twitter in current form to be all that bad. I don't know why but I don't see many bots, (I'm not that active and maybe not worth "botting"), and mostly see items in my areas of interest. I also don't see many posts from what I would consider the lunatic fringe. I haven't done any active filtering so I guess the algo is working for me.
If you only focus on those you follow, and don't post much, they aren't that visible.