I'm going to try to make sense of this madness. TL;DR, to no one's surprise, Team Magma is a lot more realistic, and more importantly, sympathetic than Team Aqua.
Historically, Team Magma's goal of land reclamation is nothing new. The Dutch did it, the Arabs did it, and the Chinese probably will somewhere on the globe if they haven't already. They just went about it in a comically stupid way because they figured erupting Mt. Chimney over and over again would take way too long and draining shallows would have dire concequences down the line. "Fuck it, let's get a pokemon to help us instead, and legend has it there is exactly the pokemon we need just below our feet!" This way of thinking fits the game's theme of working together with pokemon, but in a heavily misguided sense - one that Maxie himself comes to realize in Emerald.
Team Aqua's plan is beyond retarded in nearly every context but one. This sole, hypothetical context would be if Archie dropped the bullshit late in the Seafloor Cavern in a plot twist and revealed that he planned to rule the world from what little land was left. Think about it for a moment. Expanding the sea is much more sinister than expanding the land. Who does it benefit besides his group of eco-terrorists? Like, for fucks sakes, the man looks like a pirate in both designs. Is this really the kind of man you can trust when he says expanding the sea will benefit both people and Pokemon? Archie should have just been evil from the start with the storefront attitude of protecting sea life. Maybe throw in a plot point where some of Team Magma's earlier schemes were harmful to the environment.
Yea, I'm pretty much asking for Team Skull and Aether Foundation 0.5 at this point in an Emerald remake that may never exist.