Rogue Genius Games created the neat Pathfinder class Witch Hunter. At level 1 a witch hunter gains the extraordinary ability Witch Sense:
After a witch hunter spends time in a terrain, wilderness area, or community, he can determine if a witch has been in the same area recently. A witch hunter must be in a specific terrain, wilderness area, village, town, or city for 24 hours in order to use witch sense. After that time, the witch hunter makes a Perception check with a DC of 30 – (level or hit dice of the highest level witch present in the area within 24 hours) – (number of witches in the area currently). On a successful check, the witch hunter is aware that one or more witches have been present during the past day. The witch hunter does not learn any further information about the witch or witches other than the certainty of their recent presence.
The witch hunter may use witch sense twice per day.
The witch hunter's player thinks the special ability Witch Sense is slow to the point of being nearly impossible to use. He's correct that compared to other detection spells and abilities (e.g. detect alignment, detect magic)—which take minutes at most—this ability is far slower. Indeed, in our campaign, the PCs are constantly on the move, rarely spending even 12 hours in the same place.
But, on the other hand, it's a level 1 ability, so it shouldn't be too powerful.
Obviously a GM can just change the rules, but what are the implications of a change that speeds up Witch Sense significantly? Will the Witch Hunter class be unbalanced if I reduce the time required to use it from 24 hours to 1 hour? 10 min.? 1 round?