IMO your snake's attitude is going to be attributed mainly to two different things; its temperament overall and how it is handled. I don't believe a hide makes a snake aggressive. The only boa I have is around 15lbs and 7' and rarely ever comes out of her hide. Yet any time day or night you can pull her out and handle her and she has never once bitten me or anyone else...She has even done some semi professional modeling and never got testy being held by girls who could barely handle themselves.
You snake is either nippy, or not. Handle her more and hopefully she will get better with or without hide - however you choose.