It might sound strange, i have been thinking in Tryndamere's design since i first picked him to try him out. In all metas, there was at least a few high elo tryndamere mains defying the odds. His design its not supposed to be very effective the higher you go among the ranks, and yet, Trydamere is there for some reason or another.
He is not even hard to counter at all, and has really good windows to punish him. He relies on core items that have been buffed and nerfed not because of Tryndamere but because other champions. Some juggers can defeat him, some divers can defeat him, ranged champions penalize him during lane phase, making him useless, and even some mages can do really good against him. That champion is counterplay at its finest. So many ways to defeat him, and yet, he might have a chance to win if the game extends enough.