In the Devon Corporation building in Rustboro City, there is a scientist who mentions that "I'm attempting a device that lets you see into the dreams of Pokémon!! But it's not going well..." Two generations later, you get to do just this in Pokemon Black And White.
As mentioned in Red Herring on the main page for this game, the Winstrates discuss how good and awesome their son is, but he is simply nothing more than another Cooltrainer on Victory Road. Like how someone is the village's best swordsman, but will find themselves to be average in the grand scale, the cooltrainer comes off as talented to the Winstrates since he is the best in their family.
Gardevoir's loyalty and devotion makes sense from an evolutionary (Darwinian that is) standpoint if you look at it's pre-evolved forms. Ralts is one of the weakest Pokemon in the series, even outdoing Magikarp and Kirlia is the weakest evolved Pokemon that isn't a sedentary cocoon. Gardevoir evolved to fiercely protect those it loved, their children, as they were so vulnerable. And think about humans, they can't fly, shoot fire or attack with their minds. Gardevoir sees it's trainer as a defenseless child so the instinct carries over.
On that note, who happens to be the main trainer in Gen 3 to have a Gardevoir, but Wally, the Ill Boy, easily one of the most vulnerable major characters in game.
The player witnesses Wally capturing a Ralts as his first Pokémon with Norman's Zigzagoon. We then see Wally give the Zigzagoon back. The Ralts, however, is at such a low level that it doesn't know any damaging moves yet. How is Wally supposed to level up his Pokémon if he can't have it fight or use it to catch other Pokémon to help gain experience?
Com Mons tend to be easy to catch even if you don't weaken them first. Perhaps he just kept tossing Poké Balls until one finally worked, and then used that Pokémon to help him level up his Ralts.
Or, he just used a Rare Candy, to get his Ralts to Level 6... boom, Confusion.
Related to the above: We see Norman give Wally a Zigzagoon when Wally goes to catch Ralts. Wally returns it. In Ruby and Sapphire, Norman does not have a Linoone, so what happened to the Zigzagoon? This may be part of the reason why he was given a Linoone in Emerald, but wouldn't Norman giving Wally a Slakoth make more sense?
Most players will have dozens more Pokemon than they use in their 6 slot limit. Perhaps that Zigzagoon was just one he caught or a baby from others in storage.
It has been heavily hinted Gym leaders have multiple teams. Perhaps for trainers who come from Rustboro for a first or second gym battle (Who are not the leaders son or daughter) fight a Slakoth and Zigzagoon.
When you are underwater, weather abilities somehow work. Underwater. Especially when a Water-type, like Kyogre, has Drizzle as its ability, and it rains underwater.
Sunny Day and Sandstorm make even less sense underwater.
On the contrary; Drizzle doesn't need to be rain water. You're in the ocean. Water attacks boosted from the water you're in. Sunny Day? Light is amplified in water. Sandstorm? You're in the ocean, the ground is all sand. kick up a bunch of sand, and you have a sandstorm.
Team Aqua wants to flood the earth. Team Magma wants to cause droughts and dry up the land. Both of them unleash a creature that can do that and proceeds to begin to do so in a wildly out of control manner. Now imagine if you weren't there to stop said creature.
Were this Emerald Version, Groudon and Kyogre would be simultaneously raising the land and sea. They aren't going to destroy or expand the world... they're going to remake it. All structures on land will crumble, human kind will fall, oceans will reshape continents. It's not the end of the world. It's the remake of it.