I'm not talking about "anti-idle" stuff. I'm talking about actually counting the interactivity... the same kind of thing could detect bots too. If players will not kick an abusive player because it will cost them time, the system should go "hey is it okay if I kick this guy?" and not penalize the players who want to complete the content for it. As it is, you can't kick players at the beginning of a dungeon, and if you leave the loot window open, you can't until everyone rolls, so you're stuck waiting at least 5 minutes doing nothing just to kick someone.
I agree there will be people who flaunt any loopholes the game creates, but they would be doing that anyway, so let's not pretend that "there may be a legitimate player" that might be impacted by auto-kick rules and instead make it the party decision to early vote kick based on specific anti-leech/anti-carry rules. That at least move the goal post from "the player is doing nothing" to "the player is forced to participate or be ejected"
1-50, you can solo/duo/trio just fine at 50/50, 50-90 you can typically solo/duo/trio if already at 99/99 or near it. 90-100 is harder without the pomanders, and if your party won't open the chests, then the boss is just harder. The levelsync on the items typically runs near to the level of the dungeon, so if you've outleveled it, it's really of no consequence, but you could previously spend 90/90 to pull the weapon out to use on the field, so you may end up with a party of 99/99 + three 10/10's if you're unlucky, and they will feel like dead weight.
Personally, I assume that if everyone is at 99/99 we can skip the silver chests. This is usually made obvious by the color of the weapon. But you're going to have players who want to pick up every chest, no matter what. Even when I play PotD/HoH I head to the exit teleport if the party has split up and it's unlocked, because unfortunately you will get players who do all split up, either to do it faster, or because that's just how they've been zerg'ing it the entire time.
I rarely see any party head straight to the teleport before it's unlocked, though sometimes players will head to the teleport and then realize someone got left behind, because they either hit a spawn trap or opened a mimic chest.