Sure faith is important.
I have faith in the training system and methodology. That is, I have faith that if I keep doing what I'm supposed to do, and pay attention to what I'm doing, I'll gain skill.
I have faith in aikido techniques. I believe that they are effective at dealing with violence. I also have some first-hand proof of this too.
I have faith in the ideals (or philosophy, if you like) expressed by O'Sensei and his followers. I believe aikido can provide a way of dealing with conflict that is neither fight, nor flight.
I have faith in myself; that I can do some of the seemingly impossible things that I've seen. So far, I've been able to, but the first time always takes faith.
I also have a healthy level of skepticism and a willingness to test myself, and the skills I'm learning.
My aikido practice oftentimes touches on my personal religious faith, but then, my religious faith touches all aspects of my life, so that's no surprising. By this I mean that I tend to evaluate much of what I do in reference to my religious beliefs. I doubt I would study aikido if I found it to conflict with my personal moral code.