As you probably know, its possible to "scan" on the map through the Fog of war to see if there is an enemy nearby. That can be done with cards like: Mine, Glyph of Frost and Bandit Minefield (I dont know if there are more cards that can do that).
I thougth it maybe would be cool if this "scan" effect would be written on the spell itself as an passive described as "detector". Because this "detector" cards already have that effect, writting it as an passive on the cards can draw the attention to less experienced players who didnt know that you could use the card that way. Making "hidden" effects unhidden, so that everybody can see/use it, is an good thing in my opinion.
Example Picture how it could look like: