Add more missions. Add side quests like the one in Cuatro Colinas, where you have to compete with someone in getting the best animals. There are a lot of people who enjoy the story, so I suggest making new missions or side missions, where you could hunt rare animals that you can only get in the missions. This would motivate other people to do missions.
#New missions
night bridge
tame quarry
I like the missions too but from what I've seen we're in the minority. People seem to have liked the recent Hunt Club test, though, and that accomplishes a lot of what I'm looking for from missions.
Maybe one of the Hunt Club tasks could be a "Baden's Challenge" where you choose a reserve that you own and it generates a small string of random feats to beat for that map like the Cuatro mission.