Trundle basically turns into a secondary support late game. His mid game is where he is strongest damage-wise. Using the stat-check argument against him is pointless since he steals stats and arguably has the lowest damage of all the juggernauts.
The only free stats he gets are an attack speed boost and increased healing, but only in a certain AoE, everything else he has to take from an enemy. His entire kit is situational and terrain focused. Also, he has zero burst damage, which the game has highly favored for quite a few seasons.
Calling Trundle a ball of stats is just as silly as calling Yi, Jax, or Trynd that. He has very low killing power on his own. If you allow him to get a carry score, your team probably plays way too aggressively.
He's bad at chasing, but he's one of the best champs at setting up traps and manipulating the battlefield. He doesn't win games by out-statting people. To prove my point, try playing him as support some time. He doesn't need a single kill to help win a game.