Thanks! The Herd action doesn't require you to have a shepherd in the clearing that you are moving the shroomlings to so you can move a large ball of shroomlings around the board.
I'm a big fan of choices in boardgames and mechanics that have to make the player very observant of the board.
You've hit the gameplay loop exactly on the head and honestly I don't think it's too stable as it is. Much like a mold infestation if this faction ends up being ignored for too long at the end of the game it can grow out of control and have a huge point jump of somewhere between 12-15 points.