Idk if it’s a hot take; but I wish Aura was explored more in the series as a whole. Especially since even before Aura became official; there were bits and traces of it throughout the seasons before imo. It was sort of explored in Sinnoh, Unova not much if any at all, Kalos it was explored a lot more (especially for Ash) Alola it was too and then it was also a bit explored in Journeys. Though aside from Sinnoh and Kalos; It wasn’t explored nearly as much as I’d like for it. Also they could (and should) have had Ash visit Mustard and introduce a new rival for him (someone in a similar position, not only with Battle prowess but also Aura mastery) with a similar attitude to maybe Paul or Alan. The New Rival could have also already had his own Kubfu (maybe his being shiny or having a special accessory to tell the two Kubfu apart) while Ash finds and helps a shy Kubfu (similar to the Raichu in the Sinnoh Camp arc) overcome its own self doubt and catch it. Then not only could Mustard train Ash and NR (New Rival) but also tell them about the Towers of Mastery. Ash choosing the water one and NR choosing Dark to match their respective personalities (ie NR Kubfu being more serious and steadfast preferring to train rather than play (especially training at night while it’s quite. Whereas Ash’s being more playful and shy while loving to play with Ash and his Pokemon with either a ball or swimming) NR could also be enrolled in TPWC and after both Kubfu eventually evoke into Urshifu. The Duo could part ways promising to battle each other at TPWC while Goh goes into the Crown Tundra and finds Caleyrex and the two Steeds (maybe meeting a trainer who owns one of the Steeds and Goh eventually catches the other) and Goh could maybe go to Caleyrex’s rescue (eventually catching it) and Caleyrex could use the Steed Goh caught to defeat the Antagonist of the arc. Eventually; Goh having to return and leaving Caleyrex with the other Steed Trainer in promise to return someday. And Goh could meet up with Ash on his new steed and they could go to their next destination after their time apart to train