Killing oracle -> Something Actually Happens
The oracle is too easy to kill.
The oracle is currently an easy up-to-+6 Le [depending on potential etc.] that any spoiled player takes by shooting her to death with arrows from a safe distance. There is no danger at all to the player at any point,* even with +Curse/Doom - since players just wait until they can remove it to own her [e.g. right before crowning].
So, I propose that one of the following changes occur:
(1) HMV turns hostile, including Leggot, the ogre guardian, Hawkslayer, etc. [easily defeated by teleport, usually not a consequence at that point in game]
(2) (1) plus a stone giant lord is summoned on the down staircase out of HMV to wilderness. [easily defeated by TP through UD, killing easy mob, or luring him away from stairs, usually not a consequence at that point in game]
(3) (1) but Hawkslayer is blocking the stairs and doesn't move. [easily defeated by TP through UD, usually not a consequence at that point in game]
(4) something else entirely that doesn't have the above problems!
*caveat: unless you do something really stupid, like use a wand of destruction to get the HMV scroll, but use it too close to the oracle and damage her and destroy the walls