With that said, the brothers aren’t exactly the most, uh, intimidating people. Perhaps there should’ve been someone above them (their dad, perhaps?) that was the true villain.
I actually don't mind them not being intimidating, as it goes to show kids that people who do bad things aren't always card carrying villains. They can be affable (like Rose) or hilariously pretentious (like the twins). But that's just my own personal preference as I enjoy villains who aren't stereotypically threatening but still manage to do some catastrophic things.
Honestly, the League Cards hold so much important information that should’ve been actually brought up in the main story...
Other than the nonsensical Rose plot, this has been my biggest gripe with SwSh plot. There were so many interesting tidbits that were on the league cards or mentioned in passing that were very relevant to the overall story that did not get more focus. Some of the most egregious ones to me were
- Bede being an orphan (League Card)
- Piers having a troubled relationship with Rose (NPC in Spikemuth Pokemon Center)
- Leon being an incredibly hard to read person (Opal's notes on past gym challenger)
- Sonia's tendency to give up easily + complicated relationship with Magnolia (Opal's notes on past gym challengers)
- Sonia and Leon's soured rivalry (NPC in Wedgehurst)
- Rose's actions not matching up to his words (Rare League Card)
- The dynamics of the Major/Minor league (NPC in Motostoke)
- Leon raising Hop (Sonia in the Budew Drop Inn)
- The true nature of Dynamax (A random Trainer Tip's sign on route 10)