Sejuani still has issues of not doing much on QSS and there's other champs with better counter engage/pick plays
Zed is still too weak, reason why he's banned in SoloQ are kneejerk reactions (STILL) to qss which only affected adcs in the first place, meaning supports and tanks still peel him off said adc and they're still good to go.
Rek'sai never left....
Taliyah's waveclear nerf hit her EXTREMELY hard, we'll have to wave if anyone picks up her "buffed" state but that waveclear nerf really did a number on her
Kindred suffers from being squishy so cc and burst prevent her ulti most of the time and qss isn't an easy item purchase for her.
Most champs aren't able to do multiple situations and function or don't benefit their strategies.
Well Lee Sin, I'm actually surprised with just a shield/sustain buff he came back O_o. So I'm guessing since a large amount play him even when they shouldn't, he's suffering from false performance information. But I don't think the buff wasn't reasonable.
Jungle will always been tier based picking, unlike laners junglers affect everything from level 2, where as laners only really impact their lane+another role until about 10-15minutes in? So jungle always has to be a top tier pick or else you just won't have the lane pressure/clear speed or transition to mid/late/end game well.
However I don't see this "4 jungle picks" you're seeing.