Nighty night, Dragonite
Just rewatched the episode and my opinion has changed a bit compared to my initial thoughts. This was actually a passable battle, with the upper hand being traded throughout the fight. Flygon was tossing around Dragonite without making Ash look completely helpless as I feared, forcing Ash to adjust his plans to accommodate Gengar G-maxing to even it out. Gengar eating sand was a genius strategy. If you can't beat 'em, eat 'em!
I'll admit calling the animation terrible was far too harsh and an impulsive overreaction on my part. Yeah, it was still bad and very underwhelming for a battle this important, but it wasn't a slideshow. The perception of a battle is largely affected by its visual presentation. Even if the writing is good, that intensity has to be conveyed through what is happening on screen. My reaction upon first viewing the episode was as a result of not looking past the mediocre animation, but after watching it again I was able to appreciate the writing choices and intentions behind it. The ideas were definitely there despite the presentation lacking.
I deliberately saved mentioning the final matchup for last because what was that? I can put aside the training montage of events that supposedly happened offscreen, but why was Raihan just standing around while Lucario charged his super-mega-max aura bomb?? Seriously, what is up with all these opponents securing their own losses and handing Ash a victory. Iris stopping mid-battle to teach Dragonite Draco Meteor and now Raihan staring at Lucario's new powerup in awe and waiting until it's charged before attacking. Also, for what is supposedly Raihan's ace, Duraludon did surprisingly little to live up to its status. Flygon deserved the ace status here for handing Dragonite its first L and nearly giving more fuel to the Jobgar crowd. At least there wasn't comedy. These next PWC matches seriously need to step up their game, we're in the big leagues now.