A persons attitude is what controls everything. Their will and determination is what makes someone likely to succeed. Intellect and emotion can go a long way but you can have all the intelligence in the world but without the will to do something it will never get accomplished the best it can be accomplished.
Intellect and emotion are excuses for us to behave like animals, rationalizations that we make up to ignore the fact that we are no different from the rest of the animal kingdom. Our humanity, our goodness, it primarily tied up in our autonomous will, or, in so many words, our ability to choose.
I definitely think that human will is stronger than intellect and emotion. While it is important for some to strive for intellect, it can only take a person so far when it comes to the will to achieve a goal or objective. Emotion is not something I think is even in the same category.
No, human will is not superior to intellect and emotion, because we are servants of our neurons. Neurons and the way the brain functions controls how we think. It is brain functions that allow us to have certain emotions. Will power and the human will really has very little to do with it.
The only reason I'm saying no here is because it is a bizarre comparison and really a false dichotomy. How can intellect and emotion be grouped together and compared with will? If anything, will is closer to emotion than it is to intellect. As to which is the most superior, probably intellect.