More one brand-new suggestion, here I go!
-What's dive?
Dive is like the ability "Ride", but underwater. Whereas that the speed of the character underwater is relatively low, this new ability will increase its speed as "Ride" do.
(Yeah, I know that sometimes "Ride" decrease your speed, like using Venusaur's "Ride", but it doesn't matter for this topic.)
-What Pokémons can use Dive?
The same Pokémons that can use "Surf".
To make the game more like GBA. Instead of using ladders to reach underwater, it would be better put dark squares where you would use commands like "!D2" and "!D1" to sink and climb underwater, respectively. This second suggestion will make "Surf" useful, considering that everyone uses "Fly" to be more practical.
-What's dive?
Dive is like the ability "Ride", but underwater. Whereas that the speed of the character underwater is relatively low, this new ability will increase its speed as "Ride" do.
(Yeah, I know that sometimes "Ride" decrease your speed, like using Venusaur's "Ride", but it doesn't matter for this topic.)
-What Pokémons can use Dive?
The same Pokémons that can use "Surf".
To make the game more like GBA. Instead of using ladders to reach underwater, it would be better put dark squares where you would use commands like "!D2" and "!D1" to sink and climb underwater, respectively. This second suggestion will make "Surf" useful, considering that everyone uses "Fly" to be more practical.