Muku
Member
Well the water Pokemon aren't actually made out of water. Most of them are based off aquatic animals. Go set a turtle, penguin, duck, fish, etc. on fire and see what happens.
EDIT: I've never actually done that, just saying. Pretty sure they'd burn.
I know, however, some really shouldn't be burned. Hell, they probably shouldn't even be living out of water. Magikarp comes to mind. Haha. My point is some probably don't belong out of water to begin with, and well, they wouldn't be set on fire in the water. Pretty sure there are a couple of Pokemon that have slime or something within their description which probably should prevent them from being burned as well. I dunno. I feel like they don't add stuff like that because they don't want folks to favor them in certain situations or something.
Edit: Though my main frustration with burning comes from TCG as of late. Hopped back in with the iPad app. Card game has changed a boatload since I've last played years ago.