Agility: Skilling island agility has always been useless.
Put an agility course or multiple courses on the island, have them circle the other skillers. Make it similar to the wilderness xp rates. Keep the obstacles to where you can fall off but not into Pits below ground , this will help people running the course keep up on conversations with those around them without missing a message due to a fall. Agility is usually a lonely skill to train and skilling island is all about community interaction.
Firemaking: Rows of logs to set on fire. We all know firemaking is useless and is a skill no one trains with others, again taking a skill that is lonely to train and give the skiller some community around him.