Since 9.0.5, Assassination Rogue has established itself as a very solid melee DPS spec. The single target damage it brings is very good and, in addition to that, it offers some bleed-cleave damage for bosses like Huntsman.
Vendeta is a strong cooldown every two minutes that gives it the strongest burst windows among the three Rogue specs. With
Insígnia de Zoldyck and
Ponto Cego, Assassination also has some execute focus it can bring to the table, which is particularly handy for demanding burns like phase 3 of
Sir Denathrius. Another advantage of the spec is its relatively slow pacing in single target situations. The spec is fairly easy to pick up for newcomers and the speed of the rotation allows more head capacity to focus on boss mechanics and situational awareness. "Optimal" AoE damage is not that impressive, a bit harder to do, and requires some build changes. However, AoE is usually not the reason why Assassination Rogues are brought in. If you are a multi-speccer, this can also easily be remedied by swapping to Outlaw.
Rogues have some personal cooldowns that are nice. Movement bursts come in the form of
Disparada and
Passo Furtivo, alongside potential covenant signature abilities. For personal survivability, there are solid defensive options through
Evasão,
Manto das Sombras, and
Finta.
Where the spec is lacking is raid-wide utility. It does not have a raid cooldown or buff. Boss design in the current raid leads to raid rosters usually favoring a lot of ranges. For the remaining melee DPS slots, a raid lead will often be likely to fill most of them based on raid cooldowns and buffs and only after that based on whatever best DPS is available. This tends to leave not many spots left for Rogues in the current Mythic raid and single target DPS is the main selling point that Assassination tries to fill here. At least, it is pretty good at offering that and I am sure fans of the spec are happy about the increase in throughput we saw with the last patch.
As far as statistical performance metrics go, Retribution is currently about as middle of the pack as you can get as a DPS. It provides strong burst for both single target and AoE on a relatively low cooldown with abilities like
Ajuste de Contas Final and
Preço Divino, and although its sustained single target damage isn't especially strong, its burst is enough to keep Ret competitive with other DPS. In particular, it's a good spec later on in the instance, as
Bênção de Proteção is useful utility on the last three encounters, which are the most difficult fights in the raid. Damage-wise, Ret's performance is also quite a bit better on these bosses than some of the earlier encounters.
As mentioned above, Ret's single target damage is a bit lackluster outside of its cooldowns, and although the 9.0.5 buff to
Veredito Final has certainly alleviated some of the issues, it's still comparatively weak in this area. Fortunately, there are plenty of bosses in Castle Nathria where burst is a lot more valuable anyway, especially bosses like Sludgefist that heavily favor Ret's cooldown durations, so this hasn't been a problem that has made a large impact on its performance as of yet.
Overall, Ret is still a decent melee, but although it's certainly still a viable spec to bring to progression, these days you need to be more than decent as a melee without a raid buff for people to be excited to bring your spec to a raid.