In the old timeline, he's a general and shows up to stop Taven in Armageddon. In the new timeline, he works with Mileena and is nearly killed in the komik (why have I not seen "komik" spelled like that?) and is then defeated by Kota Kahn then D'Vorah in the game. Outside of that, Rain has done nothing. He really should do more. Maybe he should gain his own rebellion to take Outworld or something. He's my favorite character and I'd just like to see more out of him. I don't know. Tell me what you think about Rain.
I, too, think he's an awesome character. He's far from my favourite, but he is one of the coolest characters and I liked him since his debut in UMK3/Trilogy. Unfortunately, he'll never outgrow the "Purple Rain" from Prince cliche but I would like to see him play a pivotal role in future games.