Just for discussion's sake: what would moving all of this changed?
Had we expanded on the Tomo battle and seen all of it, by the implication that was made of Ash saying he'll "oneshot every one", all we would have been seeing is Greninja sweeping quickly. Then we would complain that Ash's other pokemon didn't get the chance to shine.
Now, say that we had a whole episode to feature the Top 32 and Top 16 together, sure we would see more from Ash's team, but what would be the value? Seeing him curbstomp? Sounds like a waste of an episode in a small way, doesn't it? It all comes down to a double-edged sword. If you want one thing, you have to be willing to sacrifice another. Personally, I'm more willing to sacrifice curbstomp battles in favor of a cohesive storyline.
I guess, what I'm trying to say, at the risk of rambling and sounding repetitive, is that XY has always been a different series. This League isn't like other Leagues. It's not a battle fest with only one meaningful battle (if we even get that), but a story with four meaningful ones for Ash as a character. When one stops seeing it that way...holy crap, the episode becomes a LOT more enjoyable. Maybe it's the writer in me, but I guess I'm trying to help everyone who disliked the episode come to see it in a different light so that they can enjoy the remainder of the League with positivity rather than relegating it to "worst League ever" based off of one episode, some summaries, and an expectation that the writers may not be trying to fulfill (or are fulfilling in a different way).