I find Tryndamere to be obsolete these days. My thought? Mocking Shout sucks.
Tryndamere's been out of it for basically over a year now because he gets easily outmaneuvered and outperformed by others. Sure, he can kill virtually anyone in a 1v1, but no one is stupid enough to do that with him. And in team fights, his poor approach options and weakness to kiting make him ill-suited for such fights.
My thoughts on why this is? Mocking Shout.
Hear me out: Tryndamere's got an okay kit for a fighter. He has bonus AD and crit chance passives based on his missing health and Fury, respectively. He's got a gap-closer from his E, and he has an ult that can let him pull off some exciting (if predictable) gameplay. And then there's his W... The slow on it is unreliable, as it generally relies on your enemies having bad ping, but the fact that it lowers enemy AD by 20-80 makes me think "ancient mechanics" or "invisible power". Sure, it works on ADCs and AD assassins, but oftentimes that AD reduction isn't even noticed when the enemy mages or tanks annihilate Tryndamere anyways. And Tryndamere is no assassin, so him getting to the enemy ADCs is pretty hard to do when he'll just get stunlocked to death or Exhausted.
To that end, I think Mocking Shout needs to be made different somehow. As for how, I'm still debating that. Maybe something along the lines of "affected enemies deal X% less damage to Tryndamere for a few seconds" rather than just reducing AD.