Vernikova
Champion
i would say he does have a better chance thanks to pikachu anyway coz like in all leagues and new regions he dont have any of his most powerful pokemon coz he dumps them to start new and the only reason he won the battle frontier was coz he had all his old (original) and most powerful pokemon like charizard who is a total legend by the way and i personally think tht charizard would be ash's only hope to win against the elite four
my opinion anyway, sorry i rambled abit lol but it is all true lol
You can't really say that he would win the Sinnoh League if he brought back his older Pokémon. You have to remember that he lost the Silver Coference even though he had Pokémon like Charizard on his team.