So, I just saw an A Rank in Azys Lla get killed by 30-60 people within 20 seconds, and I didn't even get there in time. To be honest, a fix for this is extremely needed.
Sure, you'll have the people who've gotten their i180 gear already not deal with hunts anymore, but the main problem lies in an enemy's HP. ARR Hunts weren't as bad since they were nerfed in rewards. The current HP of these enemies(against anywhere from 60-100 players) makes it nearly impossible for 90% of the players to get their Centurio Seals. Rather than what OP stated about increasing a Mark's HP based on amounts of people, just buff A-S Ranks straight up so that you need at least 50-60 people to reduce their maximum health by 5% at least(dependable on gear).
If possible in a future patch, please make hunts not gate i180 gear.