X3's Storm was more true to the character in terms of her sheer power displays. Bryan's Storm was very romanticized and softer in tone. I think most fans wanted a more hard, regal character who was a leader. Both X2 and X3's "Storm" characters were extremes but technically, the character needs BOTH to form a complete and accurate portrayal of the weather Goddess. But I am not sure Bryan can find a balance between the two. I have a feeling he will just avoid the idea altogether and keep it moving.
That said, I do want Storm in this next film. Since it's DOFP, she needs to be there. However, they do NOT need to have Halle Berry's presence for a cameo to accomplish that. I could do without Halle at this point--her life is f***ed up as it is--just in real life.