Not sure if this is the right place (PF vs DF)

[Anova]

In general, nobody will speedrun any dungeon below Lv.50 so you can rest easy on that. Also, speedruns do require a minimum amount of equipment to work, so DF parties are not likely to do it unless everyone is i90 or higher. Most players when they receive the message informing them there's a new player, will not do a full speedrun. If enough players are overgeared, they may pull 1 or 2 mobs at once, but never the entire train. Good parties who do this will tell you specifically when they are going to stop and teach you the speedrun mechanic. If you run normally, there usually is only 1 trick you need to know for each type of enemy to handle them. They'll tell you the basic boss mechanics though as those are always the same whether it's a speedrun or not.

As for the Copperbell Mines boss, it sounds like somebody did not explain the fight or the intended strategy to the tank. The adds on the last boss cannot be tanked. They will relentlessly attack the wall until it breaks and release a flood of adds. Once that wall breaks, the adds can be tanked, but usually, the boss is dead by then. DPS can delay them by killing the adds, but melee have a hard time running back and forth between the adds and boss. Tanks will sometimes move the boss closer to adds for the dps' benefit, but there's no point for tanks to build up enmity on the adds. The strategy where you simply focus on the boss and ignore the adds is the anomaly, called the burn strategy.

The burn strategy for copperbell boss was not the standard run but one that evolved for getting new players past it. It is designed to be simplified, especially on the dps and tanks who might not know where to position themselves optimally to direct the boss' aoe attacks away from the other party members and help the dps constantly attack the adds and boss. It also places some pressure on players being overgeared (more than the lv.15 quest armor/weapon and lv.5 accessories most players would have on the first time) to kill the boss before the adds pile up and kill you. It makes the fight simpler but the downside is that after enough new players have been taught that method, it becomes the new standard, although it is intuitively not how the classes should be playing in that fight. Another case-in-point is Coil T2. I highly doubt the developers intended for players to wait 8 minutes dancing outside the last boss for the countdown to reach 0, nor to break the usual party dynamic of 2 tanks, 4 dps, and 2 healers.