Sound should be your warning system. As for radar/map, I don't want it to dictate where I go. I want my visuals and curiosity to do that. "Oh, looks, there is an old ruined tower, lets go check that out!" Rather than, "The map says this is a dungeon" or "My radar says there is treasure and enemies here". I want to be intrigued into exploring, not explore for the sake of playing the game. For instance, Skyrim did this... they had markers for dungeons and stuff you could explore, I want it to be much more natural than that.