It’s important to note that this graph is only as good as the data entered into it. There are MANY factors that directly impact damage at the subclass level, including player level, equipment, buffs from other party members (group composition), consumables/flasks, masteries, feat selection, and ultimately the player behind the character.
What this graph doesn’t show:
A true representation of overall class performance. The Raid Bosses introduced in Regisfall so far generally don’t involve large numbers of incoming creatures or a strong demand for crowd control. This naturally favors subclasses capable of focused single-target damage, while placing subclasses that excel at AoE or CC at a disadvantage in terms of how their overall impact is reflected here.
For example, classes that are very effective at clearing lava spawns in the Burning Depths may appear to contribute less damage to the boss itself, even though their role is critical to the success of the fight. That impact is not represented in this data.
Some damage sources, such as conventional poisons, and damage from pets aren't calculated here. Beastmaster for example gets a high portion of its damage from pets and since that damage is not being dealt from the actual player mobile, that damage is not factored into their average.
Other points to consider:
Sample size matters. Some of the subclasses represented here have a very limited sample size in the amount of boss fights they've had logged. These can range as low as 5 fights or as high as 180 fights. As a result, those classes with smaller sample sizes cannot be weighed as heavily as those with large ones.
Player experience and mechanical knowledge have a significant effect on character performance. If the top 10% of Berserkers deleted their characters and created Bounty Hunters, the average indicated performance of Berserker would drop, and the performance of Bounty Hunter would rise. True balance can never be achieved through mechanics alone, as much depends on player inputs.
These values are taken as part of a 5 player group. Some of the subclasses which excel in this setting do not necessarily perform well in a solo setting, or in PvP. Different subclasses have their own strengths and weaknesses in the game world and it is important to consider that many of them are not reflected in this data.