>>51679035On paper? Goh. He has the widest range of Pokemon and, even some of his that aren't legendaries would be powerhouses in battle.
But, there's more to battling than strong Pokemon. Goh isn't an experienced battler, and has been shown to freeze up when he doesn't know how to counter his opponent. He can sometimes strategize, but not consistently.
I agree with those that said Iris. Even though we only ever saw her lose in PM19, she held her own against Ash when they battled and made it into the M8. Some will say Cynthia went easy on her, but regardless, she didn't get curb stomped. So yeah, Iris.