I am a big fan of Bozja's Critical Engagements because of their spectacle, if I envision S Rank marks as world bosses, this is how I would implement them.

Grandiose, timed, reasonably difficult encounters with stat sync at designated stations in the open world to queue for server-wide and with a limited number of participants, but a shorter cooldown.

The current Hunt, at least for S Ranks (I enjoy A Rank trains) I only engage in because of the rewards, not because the encounters are so fun to play. I guess it's pretty thrilling to worry about whether you make it in time or not whenever you play during prime hours . Other than that I don't think there's much that draws players to hunts naturally. In fact for new players who are not hopelessly addicted to the game and want a prestige mount, the hunt would usually immediately drive them away, it's a very hostile kill or be killed environment. If you don't cut someone else off from getting the mark, you won't get it yourself. Because hunts don't scale with player number well. They work with a small circle of hunters, but beyond that it turns into a sh*tshow of instant congestion after the announcement. You have to wait by the aetheryte, server travel window open to be able to instaswitch worlds. It's basically a mild form of clicking a sign for 24 hours to get a house. If you spawned, well thanks, let me pull it for you.

Would anybody prefer a more CE-style implementation of Hunts if it were reasonably feasible? If I was a new player witnessing this in the open world, looking at the arena from the outside, seeing players getting blasted by a larger-than-life boss, it would probably intrigue me way more than map-crushing armies of people instakilling an obscured by fx boss which can barely defend itself for the few seconds it's alive. The first one is playing a game to enjoy it, the second one is farming for a meaningless virtual reward no matter how mind-numbingly dull it is.