A and S ranks are pretty much a free for all, and, with the increased server traffic and higher item levels, A/S targets die in SECONDS. I think the system should be replaced. Clan Centurio should implement party based hunts that would be:

1. Repeatable and weekly, like B ranks but not in the open world.
2. Require, or at least recommend, forming a light party or a full party.
3. Completing a short tracking quest of some sort (ie: go here and /lookout).
4. An instanced fight, similar to the mobs that defend treasure hunts. No one outside your party can participate. Only your group gets to fight. Monster is adequately challenging for a party, not appropriate for single combat.
5. Available in two difficulties (A/S)

No more free for alls. No gambling on spawn timers. Weekly rewards. If you die too bad, better luck next week, or you can stick it out with the free roaming A/S marks.