From his origin he was definitely arrogant. Lambert, the writers and directors built on that with a touch of humour yet still solemn and respecting Elder Gods and rules. Of course that's Hollywood as well, but I liked a light touch to Raiden. I actually prefer the more serious devout god being Fujin and the more sinister, crazy, dark yet a bit of a smart ass who won't back down from breaking the rules in Raiden. In 11 they've kind of mixed it all up a bit, though Raiden is full on serious, yet still has the touch of arrogance. But from the start wanted to be seen as a god, thinking he knows everything, has little faith in earthlings and just wants them to do the job. It's only later he develops a relationship of understanding and empathy. He has a tendency to darkness as well, which doesn't even come out in the movie, since MK1.