>>42240784The thing with May's rivals is they had a dynamic with her that actually worked, it let you see a different side of May's character that wasn't there before (May got much more snarky, competitive and lost her temper a lot when they appeared), and they also drove her development.
Dawn's dynamic with her rivals pretty much stayed the same the entire series. The Dawn/Zoey dynamic doesn't change at all from their first appearance, Zoey just continues to be somewhat of a mentor to her and it stays like that the whole run. Kenny is just the boring childhood friend Dawn doesn't like. Ursula didn't appear much to get any development. And Nando just didn't feel like Dawn's rival since he was more Zoey's rival.
Hell, I even say Jessie had a better rivalry with May than Dawn despite losing every Contest in AG. They actually rivalred over Wurmples, Beautifly/Dustox, Jessie wanted to capture Skitty before May did, Jessie started working with Harley to sabotage May and he lent her his pokemon, etc. I think Jessie had the best rivalry with May of all the girls.