I can’t exactly tell if Arthas’s head looks too small or his shoulders too big, maybe both.
The head gives the impression of Arthas being a slim man, while the armor suggests a muscular body. Is it actually a mech suit from the gnomes?
Big shoulder-pads are an important art style of a WarCraft game, but these are too much and look like metal airbags.
At least the left shoulder should not be higher than Arthas’s eyes, to allow him to see enemies approaching from this side.
Also, while the units proportions are better in Reforged, the buildings feel a lot smaller in comparison.
If technically possible, the units would look better if they were e.g. 33% smaller while keeping the new proportions.