>>54313344Iris, then Misty, then Brock, then Clemont, then probably Kiawe, and then the rest. Out of all of Ash's companions, Iris and Misty were the ones whose primary goal centered on battling. Misty's dream to become a master of water pokemon, and Iris' dream to become champion. So they'll go farther then the rest because of that. For example, Brock might be higher if he weren't more interested in breeding/medicine as his goal. Whereas he's shown to be an excellent battle trainer in spite of this. It's largely the same case with many others who aren't battlers first and foremost, those more interested in pageants or inventions or just filling out the dex
On a related note, you'll find that Misty and Iris are the companions that Ash himself has battled against the most (unless I'm mistaken, I admit I only watched some seasons partially)
