It isn't that hard to tune multidoters, you don't even have to tune them specifically if that's going to be their niche. The problem in turn is that, lets use Shadow as an example, they also have superb single target which they shouldn't if their niche is going to be multi-dotting. Yes they should do about 75% of a spec that doesn't have the option of multidotting on pure single target. Otherwise you end up in a situation, like right now, where you literally have the top US guild running 8 Shadow Priests and are still struggling to beat the encounter because of a tight enrage timer.
A dot class should never excel in single target, AoE, multidot, and burst AoE all at the same time without having to even swap talents.
https://www.warcraftlogs.com/zone/st...unt&dataset=90
https://www.warcraftlogs.com/zone/st...gregate=amount
This is exactly my point, first 5 in Dazar'alor have a huge lead over any other dps, and they're all multidot classes and several of the encounters DON'T HAVE consistent multidot opportunities. Even if you shift it to a mostly single target fight like Grong specs that are supposed to excel in single target are a good 6-7k behind Shadow Priest.