Wow, you're trying to totally spin my words out of context in some weird attempt to vilify me...
I only have a problem with off-screen progress when it's done in a manner to shove in what SHOULD be on-screen progress (Ash's PWC rankings/matches being skipped after wasting episodes after episodes with fillers), or completely lacks narrative basis (Iris becoming Champion when she showed no intention in the League structure during her series). You're the one who's trying to remove that point of contention to push your own point across.
Sure we do, we have a rough idea about League structure, at least established ones, from DP.
Dephender said that it is: Gym Battles (8 minimum) > League Conference > Champions League > E4 > Champion.
A Grand Festival is comparable to the League Conference at average. Yes, the method of qualifying and winning is noticeably different, but Contests and Festivals aren't about showcasing strength, not like the League Structure anyhow. Not to mention that Leagues have more steps involved that demands a steeply increasing power curve. There's no way it's believable that Iris beat the likes of Shauntal, Caitlin, Alder etc. because there's no on-screen basis of her even having any intention of challenging them, much less the power.
Am I 'dismissing it'? Back in BW, Iris was clearly below in Ash in terms of both experience and power level. It was clearly evident that he was the better trainer even with a dumbed down psychology as well as weaker Pokemon. The only narrative basis that Iris has was her Dragon Mastery goal, and protegee to Drayden (hence me saying that the Opelucid Gym Leader position would have made far more sense).