>>57276830It's probably because he treads a pretty fine line between obviously a teenager and young man with a bit of muscle. He's not as dainty as other younger adult male Pokémon characters (like N) but he's definitely not exactly buff either.
Artists just have their own preferences and tend to change the characters they draw to fit their preferences (which is also most fanart of female characters gives them bigger asses and titties). Only a few manage to hit the sweet spot with Arven, unfortunately.
