Yes he is, even if he isn't the main character as Vincent is. Cloud appears near enough when the WRO have a deadly battle against Deepground; Tifa, Yuffie, Cid and others appear too at the time.
It's a pretty good game. It's really more of a shooter game since you play as Vincent Valentine. I would recommend it if your a FF7 fan since it gives more insight into Vincent's character and past.
Cloud is in no way what you would call emo. If you ever played the game you would know this. Cloud is depressed in Advent Children for a bit but for a good reason. Give the guy a break, he's human...