I just watched the episode with subs (the official Japanese subs, calm down!)
The actual episode was okay. Bisharp was cool, but Charizard and Greninja was disappointing. Two rivals using their aces should be one of the best fights in the series, but it was over very fast and the only thing of note to happen was the giant chakram that apparently just KOs the user.
Considering the writers have been building up to a win with Ash and the fact that they skipped half the league just to show the finals, it was very disappointing. While I'm sure this fight will mean something to Ash and Alain's relationship and Ash-Greninja will probably get its chance to shine in the Flare arc, I'm not sure it'll do much to redeem the Kalos League, where the only genuinely good fight was vs. Shota (they focused on having Greninja and Sceptile actually fight hard rather than working out how to make Greninja job the fastest).
Been said a million times already, but Ash really had no reason to lose here. Beating a Dragonite and becoming the Orange League champion didn't affect Johto, beating several legendaries in the Battle Frontier didn't stop him from entering the Sinnoh League. Why would beating a Mega Charizard and being the Kalos League champion affect the Alolan trials? What are the writers trying to achieve here? There's no danger of Ash advancing too far or getting too strong, because he always ends up being one of the region's strongest and then loses to the first Pokémon he sees in the next region regardless of his performance in the league.