“A lion, snake, goat hybrid? This is the nightmare scenario.” -Kurokami
I think there will always be a level of metagaming when playing D&D.
Some monsters have very well known weaknesses. In fact, creatures like vampires, werewolves, and trolls are infamous for their weaknesses. I think, rather than make that knowledge scarce, it’s more fun to make that weakness scarce and ask the players to quest and find it.
