Okay for the triplets, sure, they were arguably the most forgettable of the bunch due to lacking relevance in the plot anywhere else. But for the other gym leaders, I disagree. Elesa finally convinces Bianca's father to let her grow up. Brycen assists you in Dragonspiral Tower. And Skyla is shown aiding an injured Pokemon. Not to mention except Iris have a secondary job. There easily the most remember-able of all leaders we have.
The Kahunas and the Trial Captains are indeed memorable though not to the point of the Unova Leaders. There characterized well, though aside from the trial, they don't have too much influence on the story other than the E4. Though I'd like to say the Trial Captains are more likable since you have to go into daily life to battle them, fleshing them out.
On a related note, I like how HGSS also provides life for the gym leaders. Like Janine bringing food for her father, or providing a bit more on Jasmine's shyness. Another nice thing they improved in the remake.
She might as well not be a member. Her only purpose was to enable entry to the secret levels of Lysandre Labs. They could have done that any other way. A more interesting take on the XY plot could have been wait till you reach the champion then: Oh Team Flare is about to attack from Lysandre. Malva would then try to stop you from leaving to buy time. That would have been a good plot twist.
Wow, your right. I usually remember characters ( Even the forgettable ones, yeah, I'm a big Pokemon Nerd. ) But I can barely remember their names, yet alone which one they belong to.
If there's anything good about the Team Flare, its their music. And the fact that the anime and Pokemon Generations portrayed them much better.
That's not really an unpopular opinion. The story was interesting, with characters having a lot of personality, just too wordy. Sadly, all rivals are probably gonna be like that. They made it clear in Let's Go that they don't do Jerk Rivals anymore because they feel that they have better ways to show off the rivals through visuals. ( Don't think its a good reason: Just because better graphics does not everyone has to mean everyone has to be pretty. I doubt SwSh will have a large post game, because GF doesn't think most fans ( aka children ) will sit along to play it. If anything, there's gonna be a small episode, a vanilla battle facility, and some legendaries to catch.