>>36349104There are a total of 466 NPC Trainers in Ultra Sun and Ultra Moon:
https://gamefaqs.gamespot.com/3ds/210930-pokemon-ultra-sun/faqs/75389Bear in mind that that's Trainers, not even including the NPCs who don't battle you. There are hundreds more of those. Do you honestly expect Game Freak to abandon stock Trainer classes and make unique designs for all of them?
More importantly, do you honestly think that if they DID make unique designs for every NPC Trainer, we wouldn't just have fewer NPCs to compensate? It's a completely unrealistic expectation to have that kind of variety.
I'm kinda with
>>36349125 that this would be reasonably feasible and a good way to keep different Trainers interesting - as long as it could be automated broadly and applied to every Trainer class, not redefined for each class, anyway - but giving every NPC a different design anywhere beyond this level is simply beyond what Game Freak is capable of and WAY outside of the scope of what their priorities should be.