Trundle and tanks
Can't say I'm best Trundle player, but I'm trying him every season and every season I'm not finding him useful, because of his kit based on his AA. Even after rework nothing really changed. No true cc, tankiness that depends on his ability to lifesteal with AA while standing on one place (this is just rediculous). His passive is useful only in lane, and not really useful in fighs. Positioned like anti-tank champion he can't truly do anything vs tank, becaus they all have hard cc, and that prevents him from AA. Most fighters are casters or have insane damage, while Trundle has nothing of it.
Same on lane - he can stay there easy, but still suffer from popular meta champions like Irelia or Fiora, because they can prevent him from attacking. In soloq he's totally depending on his carries, because all he can do - is peel for adc, but there is still better champs for that. Fed Darius even while kited can flash + E and burst down squshies, while kited Trundle won't be able to do anything. Slow enemies and then what? Even 1v1 there is no guarantee that he'll kill adc.
Sad but right now Trundl is very specific team dependant pick. While tanks grew up in last patches there is no thing that can tame them.