Describe the feature you have in mind.

I suggest increasing the range at which undead mobs flee to when scared by a gargoyle.
Ideally it should be configurable, but having looked at the code that might be finicky.

Does this solve a particular problem?

The default undead scaring range is very small, temporary, lasts only a second or two, and costs a resource to activate. Skeletons don't even run out of range of their bow and melee undead just reacquire their target after a second of being scared. Increasing the distance the mobs flee to, or giving the player the ability to increase it, would cause mobs to flee for longer and give more options to use this really cool and thematic feature.