Ok, but does this mean that whenever someone dies, the boss difficulty goes back down?
Any counterstrategy to this, or moreso 'just assuming that bosses will lose strength again when someone on their combatant list dies'? I'd have no specific problems with that myself, but it's interesting enough to think about.
What if we incorporated flag status into the consideration?
Say there's an 8-man party boss. The boss has a zone around him that tracks any player action, including movement. As soon as a player steps into the zone, they go on the combatant list. If that person is the 9th+ on the list - they contribute to the stat growth of the boss. The stat growth could just be a few %s per additional combatant, with several steps of anti-zerg mechanics ramp-up. Any non-movement action generates threat.
The boss' nameplate has general dmg trackers (shown in %s), visible to anyone (though this could be argued against). Any attacker gets their own line in the tracker. Parties are shown with their leader's name, same for raids. Threat values are only visible to tanks who've casted a particular ability on the mob (this is my personal preference and could be omitted for this example).
Flagging up starts to remove your threat value on the boss (say, 2% a second). While flagged, you will generate 1/2 (or maybe lower) the threat per action. If your threat goes away completely, you get removed from the combatants list, but, as long as at least one member of your party is on the list, your party's looting rights remain. Any death would immediately half your threat. Becoming red removes you from the combatant list and removes all threat. Stepping out of the boss' zone starts to remove your threat at a greater pace than flagging up, and removes you from the combatant list immediately if you had no threat at all.
This way the starting party are encouraged to flag up first, because it would move the enraged boss onto the newcomers much faster, especially if they decide not to flag up themselves and to just hit the boss. Conversely, if the first group gets flagged upon by the newcomers, they'd definitely want to fight back immediately, because the enraged boss would stay on them for longer otherwise.
What do you think? Is this too convoluted? Would it even work? Are there huge exploits that I missed?