@Walker:
A power over rain would be really stupid. I mean maybe its cool, he wouldnt have to worry about his garden drying out because of lack of rain..but really very lame power.
He's made out to be a badass, so a logia over weather or wind would be more likely. I mean what would a rain fruit do? Cause floods? What else could it do?
Just what you said… Cause floods, which, in an archipelago World (Which is what Odaverse is) is very dangerous. I don't see any breakwalls anywhere in One Piece, which is kinda stupid, but whatever.
Plus, there's more than just regular rain. There's torrential rains, there's acid rain (Which would be awesome), And there's the most powerful force in the universe: Water pressure. A high enough PSI water pressure gun can be used to cut diamonds.
Plus, Devil Fruit powers are weakened by the sea. While rainwater has the salt content removed, who is to say that Dragon couldn't have the ability to keep the salt content in his rain? That would mean no Logia could touch him.
Plus, as Foxy showed us, Devil Fruits aren't always used as a weapon. Foxy used his powers and then used stuff such as bombs, his fists, and gadgets to attack his opponent. His power aided this, but it wasn't a direct means of attack, per se. The Noro Noro beam didn't cause damage on its own, Foxy had to render damage to his opponent physically or with devices.