Well, I was more making a joke at the curse of bad posture which afflicts all barbaric kings, but I don't think the pose and expression are bad as a compromise between the original lore and the unavoidable fact that he has this hulk-like in-game model now.
Don't get me wrong, I think the splash is severely lacking in the plague department. Needs more blistering skin and vibrancy to the raw, exposed muscle to really capture that.
However, the most important part of Trundle's original lore to me was how he accepted the disease as his source of power to the damnation of his tribe. You can't really pull off the same sense of scrappiness with the current model anymore, but I still get the sense of a solitary, yet confidant nature from this one.
Cast another ray of sunlight so that it's not just showing off his taut abs but also the lower diagonal of his face with the savage grimace and the diseased gash of his face and I think the splash would be more the business with little else needing to change.