I would like to see S ranks become more of a big deal like GW2 activities / world bosses (critical engagements is heading that direction I suppose). So a universal 'no touchy' timer might not be needed when they could have a variety of 'warning' signs and build ups.
Like King Behemoth you start to get weather across the zone that will occasionally drop an AoE lightning (or meteors..) near you (you see the circle, can dodge), and then you get DoL / DoH mission to fortify the fighting ring while DoW / M protect, bullet hell phase, and then Behemoth comes out of the sky pushing everyone back and it leads into a great big world boss fight, including things like firing rampart chain cannons, potentially providing team support and buffs with unique crafts, etc. The server would know of the event about 20 minutes before he even touches down due to the build up. Each having their own grand ordeal, and .. add a lot of them
My personal aside on hunts is that I wish we had a hunt log, tracking hunts killed, first time bonuses, which rewards are in demand, refreshing rewards, maybe a hunt train / party finder link with auto party generator based on a few prompts, and perhaps adjusting B and A ranks a little. Where B ranks become more personal spawned, and more dynamic.
Fighting in a FATE and a predator B rank comes at you, fishing too much at the pirate sea and a B rank comes out of the water (does not aggro instantly so you can choose to run away), get a ticket from the NPC and you can force pop them, when they appear whether ticket based or not they tend to be worth it (good bonus exp, cute poetic and secondary tome boost, etc).
Then A ranks might drop pyreflyes on death where you can interact for a dynamically scaled fight, with more monster hunter like fight mechanics (more skill based than stat based), with perhaps a difficultly scaler to the dynamic element that deteriorates as the pyreflies are older (meaning a more decayed aether mass is weaker, a notice-able but non-hyper punishing different in rewards based on challenge level), being sure to leave the current "alive" balance for the current hunt train mechanics but also allowing players to trek through the zones and purify locations (can only kill them while alive or pyre mode once every X time, so you can't double up on the kill lol).