Giving a XP boost to DPS instead of tank.

[Serilda]

Let's say I want to level up a DPS in dungeons because I want to test the gameplay in "real situation".
It's longer than for a tank or a healer, so the xp boost would balance that a little.

You aren't learning any more about endgame DPS from running Sastasha 40 times than you would doing any number of other low effort activities. Heck, I think I learn more from grinding FATEs than rerunning Tam Tara, even though they're impossible to lose, exploitable mechanically and the most boring possible way to gain experience. Whenever my friends roulette they seem to end up in the most facerolly dungeons possible every time