There's no need for that. It's hard to have character development when you're not in the base game. Doesn't mean he doesn't have potential. He is underrated if anything, so many options with his background and specials. His name may be Rain but he does just as much lightning attacks as water attacks. Plus he's got one hell of a roundhouse.
I see so many people hating on him out of nowhere for no reason. It's not like he's in every game (or any game lol)and is a waste of a slot that people are sick of having. He has a lot of fans, and not just the annoying vocal ones on twitter(that ever character has). After mkx and him getting a redesign and fightable, then with how much Boon has tweeted about him the last few months, only makes sense that there's a lot of hype and want for the character.