If you overenchant Stormbringer and it vaporizes, it should turn into an actual storm: a region of clouds that shoots paralyzing lightning, the same way as the storms on the Plane of Air work.

Wielding Stormbringer cuts the failure rate of the drain life spell, and only that spell, in half.

Remove Stormbringer’s automatic attacking of peaceful monsters and instead incentivize attacking peaceful monsters by giving the hero some benefit, such as lowering prayer timeout, whenever attacking a peaceful monster with it.

While you are wielding Stormbringer, you gain alignment for killing peacefuls and pets (rather than losing it).

Aggravate monster, as well as possibly wielding Stormbringer, disables Elbereth’s protection.