Let me add to that -

1. Fix render priority. Monsters / Party Members / NPCs > Alliance members (when open world alliances are possible) > Other PC's.
--- In other words, other players around you should be the ones to vanish, NOT monsters or party members.

2. Increase hunt monster's HP substantially.
--- In addition to this, in order to combat the inability for low man groups to kill, B and A rank hunts should gain 1 vulnerability stack for every 30 mins that they are up and unclaimed.

3. Add some form of zone-wide cue that alerts people that an S rank has just spawned. (Whether it be a message that pops up on the screen, weather effect, etc).