I do think there are a few systems in place that kind of cheapen the 'hunt' vibe, from the rampant relay / 'mods', cross world train of doom mowing down your own server, losing out on your own spawn due to hyper active trains, to just out leveling a content area causing a non-desirable death rate (if one wanted to participate).
My thought was to lean into some of the issues while offering some sort of counter support system. Like if you found a hunt in the wild they might not be as strong as they are now (they're designed, sort of, to handle huge crowds) and you'd get an extra reward for killing them, encouraging people to GO GO GO and 'hunt' for them (A rank thoughts at least). Then if you come to their death site there might be a pyre fly effect (FFX) and you could fight them in a semi-phased circle around where they died (phases out other players, that sphere is an 'instance' but you're fighting in the open world), the time from death determines how many rolls from normal are lost (so currently say there is 3 item rolls, for loot, then now killing it live would be 3.5 - 4, right after death 3, half time to revive 2, third time to revive 1, and then like that last bit they fade away). Strength of the NM based on time since death, and you can force the fight to be weaker. Give the current hunting log a face lift with actual hunt focus (tracking hunt kills - first time rewards too, so all B ranks first time you see them are more exciting, time till you can get rewards again, bills, etc).
For S ranks, I know there is maybe too many for this, but thinking like taking those huge events in GW2 for world boss multi-stage fights, consider making more of those out of S ranks (Odin, Ixion, Behemoth definitely apply). In which case multiple stages, as well as specific mechanics, DESIGNED, to encourage absolutely insane number of player participation like stress test designs. Those that don't get morphed into purposefully 'world scale' can go into the above system. Random example of multi-stage might be like Odin, the special weather happens, there are nodes around the map you have to find if you don't they will fly to Odin empowering him (each node giving him perhaps 1 stack buff that is consumed for instant kill attacks), once summoned his spear is in one location and him in another (designed to be a distance away), he'll start moving that way and fighting him will slow that down, crafters and gathers can help produce a shield around the spear while monsters attack the site (other players to help, can have some level differences in the FATE to open up more player point entrances), he'll reach the shield and start to break it down as the spear powers down, once he gets to the spear he'll start to leap around (and if SE wants to be insane they can do one of those huge over the top summon attack spells onto the whole zone or something, like FFXV lol), absolutely wrecking every single player but also there will be slyphs and gridania npcs raising players while monsters everywhere go crazy (whole zone fate), and players have to find Odin before he does his crazy attack again (after X times he'll kill the entire zone that was part of the FATE, causing a ripple to go through nearby zones too, I want to say those not too but I can imagine new players being side swiped so hard they're mad lol), so a bit of a DPS race. Could keep up the crafter gather / low level opportunities with aether compasses and tethers trying to make it easy for other players to pin point him and then hold him down (lower level players can bring in crafted aether chain cannons, like the bismark fight, and interact with the fight, use potions to heal, buff, raise, etc). Overall such an event would take place over like 20 minutes minimum, if you didn't get to join it then it's because the server broke or because you didn't try.