The episode which Kibago learned was animated by Akihiro Tamagawa, THE best animator of series. His episodes as such have always some big change happening in them. This is of course not only to increase audience's interest, but also to have enough frames for stock animation.
Biggest examples would be:
-Satoshi's and Hikari's command animations. Appeared in Fukamaru's debut, these animation has been used in quite a lot of the later episodes, whenever Satoshi and Hikari made commands in their usual outfits. For example, in Denzi battle, when Satoshi commanded Dodaitose
-Pikachu's Electro Ball animation. Used every time he uses the move, ever.(Or almost every time, I haven't watched all of the episodes so I might be wrong).
Of course Tamagawa himself uses stock animation too, as he reused Kibago's Dragon's Wrath from Emmy's episode.
But unlike those, Kibago's Imperial Wrath, by the nature of it's move, cannot be reused in stock animation like others, as it is a close combat move, and has no CGI magic. They can't just change the background to match, or use a colored background to "hide" stock animation. They can do it to a few frames, but not all, as most of the move's, well, moves, is mostly based on the opponent. If they animated it in a similiar fashion to Kenshiro's Hyakuretsu-ken, that is, make Kibago punch Gobitto and later add Gobitto's reaction, they could reuse it anytime they wanted, but they didn't.
And since BW relies on stock animation and CGI more so than any other series(as most of the animators seem to be newcomers), this is kind of a problem.
Of course there are other problems too, such as animators not wanting to have Kibago an active role, as it means effort, like Iwane said. But of course this plays a bigger role.
But, why would they want the best animator to do such thing if it won't mean much down the line? This is a bigger question for me to answer. In most episodes Tamagawa does, some big change in the team happens, or there is a good battle/action/interaction. Let's count the amount of the times Kibago had a big battle after DBT. ... ... Against Zuruggu in Koharu episode. Yeah... Likely due to fact he wasn't going to use Imperial Wrath, they wanted his first battle with the move as good as it can be, as he wasn't going to use it any time soon. If they did, they would likely make the battle easy to have stock animation from. Again, like Kenshiro's move.
Another big issue is actually a classic shonen/seinen trope. As I said earlier, berserk moves are only activated as ultimate kill moves...OR
they are waited until the last few episodes of the arc of the character so the character's biggest climax is waited until he/she gets many good moments without the move, and only being shown were few times, to foreshadow what is going to happen. We knew of Hikozaru's Blaze from Shinji's flashback for example, but we haven't seen it again until it fought against Ringuma after Mikuri Cup, and much later when he evolved into Goukazaru at the near end of DP. Warning: Contains spoilers for Evangelion.
Another thing to note is not all of the pawns are in their place:
-We know Langley had a bad incident with Imperial Wrath, but we don't know what, nor is it yet brought up back again.
-Waruvile is stated to be like an older brother to Kibago, but we haven't seen much of that. Obviously something is planned for those two.
Until these two big set pieces are set up, I don't think we will see Imperial Wrath much, only maybe few times here and there(stuff like Shirona's Gablias, ie battles he has no hopes of winning anyways, therefore won't be able to go crazy and ruin scenery because he would already be fainted).
This is of course assuming they will use the move as a plot point, but again, since there those two set pieces, I believe it will. The biggest questions are of course, "When?", "Against what?" and "How Iris will cope with such event?" When?
Since there is an upcoming Onondo toy in August and there was an another one in May, marketability won't be a big problem unlike what I expected, but still will be a large one. It still won't obviously happen in August, but since they are selling the stage's toys, it does mean selling the toys isn't a big deal. But ultimately, I don't expect it to be any sooner than last 20-30 episodes of BW. Against what?
Now this is a trickier question. Rocket-dan is certainly not out of question(especially considering how Goukazaru evolved and how he mastered Dragon Rage) but not highly likely. Langley is the second biggest possibility, especially considering Urara's track record(or Hikozaru's track record with Shinji). Likewise, if by some weird event Hikari does continue to be main, Urara herself is unfortunately a possibility. Shaga is not a possibility I expect to happen, nor is the matriach if she does have a Dragon. Shooty, especially if he gets his own Dragon, is the one I would like to happen, but not the one I expect. Waruvile will likely play a mentor role to Kibago regardless, but is not the one I expect it happen against, unless Satoshi manages to tame him when he evolves and learns Imperial Wrath, and Satoshi wants to help Iris with her own case, and they have a practice battle for that.
-Iris will meet a total douchebag trainer who is hyped up heavily.
-Iris will get a secondary rival that will have this role.
-Koharu? Gochimu has an unfinished business with him after all. But as goofy as that would be, I don't expect it to happen.
-Cabernet. She wanted to have revenge against Iris, so I can see they following on that. Especially considering they love to put her in great pain even though it ends up harming her own already shaky credibility and ruining most the of the potential she had(like Kengo, though she fares much better thanks to her popularity, character dynamics with Dent and comedic potential) I wouldn't be surprised if they used her as a punching bag for Iris sometime down in the line.
-Kibago will go berserk against a group of wild Pokémon after getting lost another time. Considering this is how Pochama learned Hydro Pump, as the ultimate conclusion of the episodes he was lost and was attacked by a group of wild Pokémon, and considering writing Pokémon antagonists is easier than writing human antagonists, THIS is the plotline I expect to happen.
-Kibago will randomly go berserk in a practice battle against someone. The least likeliest option as I said before is probably this, but probably the lulziest. "How Iris will cope with such event?"
Cooldown hug? Regardless, she has to pit herself against Kibago/Onondo, as per the trope. Her glowy hands will likely be very helpful too. Note 1:
This is assuming she doesn't get Kairyu to be her Togekiss of course, but considering the thing has no upcoming toys despite being the most marketable Dragon ever(it's Barney the Dinosaur mixed with an axolotl. If that doesn't sell with little kids, nothing will), I don't expect it happen. Note 2:
I do expect Kibago to have an actual active role beforehand during Season 2, before this event, especially considering Shirona battle and Shaga, but still, it is in Kibago's evolution her chance of gaining Langley's respect, reaching to matriach's hopes and getting Shaga's respect lies. Even if she managed to get another Dragon, high or low level, Kibago's status will end up juxtaposing with it. Note 3:
Of course these are just some words before Shirona vs. Iris, how the battle will play out(whether Kibago will use Imperial Wrath or not and what Shirona will comment) will likely change a few things, but I still abide by my rant and speculations until we learn more.