One thing I love about the original Herobrine story is that the artifacts he leaves behind are quite subtle. 2x2 tunnels in the rocks, small perfect pyramids, etc. All of these things are unusual, but not dead giveaways that a ghost player is lurking around. In other words, someone could at least make a case for these being natural occurrences. So I would certainly like to see a couple of variations on this theme. From what I remember, you already have pyramids covered. But you could add things like 3x3 groups of red and yellow flowers arranged in a checkerboard pattern, and 2-block-high sand pillars in the middle of beaches. You know, just weird stuff that people will start to notice after a while.
thats a good point. @everyone Don't expect every feature you say to be in version 0.1... There are version numbers for a reason. Just because we say we are going to add your idea does not mean that it will be in the next version. That is all
What if you allowed Herobrine to open doors and if he entered your house he'd leave a redstone torch in the middle of the floor? Or maybe next to the door. I don't know if this is possible but 1 random redstone torch is enough to make people scratch their heads.
The Citizens plugin adds evil NPCs that roam around, and Herobrine is among the default characters. It's still in development, but you should check it out.
No, commenting about the Citizens mod, he does walk around yes, but I made his alter and he spawned about 25 blocks around were the altar was.