Arcane has seen a lot of play in the race to world first and early progression since Shadowlands, being the dominant spec for all of Dragonflight, and appears to be starting off strong in Nerub-ar Palace. The reasons for this has evolved a bit over time though, when it was brought in Shadowlands it was mostly done for funnel reasons, since
Resonanz allowed us to benefit our single target a ton with additional enemies around. This particularly shined on the Anduin encounter in Sepulcher of the First Ones where burst funnel was extremely valuable. In Dragonflight's first half, Arcane was the only Mage spec that had a damage profile that included real burst, this especially shined in Abberrus, though it was somewhat pulled even with Frost after the 10.1.5 rework. In the last raid of Dragonflight, Amirdrassil, Mages were relatively poorly tuned on raid launch and Arcane was just "the best of the bad class that you have to bring due to
Arkane Intelligenz".
What's different now? Currently Frost has an exceptional burst profiles that can compete with Arcane's in certain conditions and Fire while quite a bit flatter can still leverage opportunities better than it could in Dragonflight, however the difference until very recent was tuning, Arcane was for a time obscenely ahead of Fire in tuning and Frost, while holding its own, has an extremely difficult gameplay loop with Spellslinger that makes it somewhat less appealing as a progression spec. Adding onto this, the raids design has specifically lent itself well to Arcane thus far, there are plenty of windows of opportunity where Arcane's natural timings allow it to leverage some vulnerability mechanics and some available funnel opportunities making it one of the more potent boss damage specs in the game currently. Unlike Dragonflight, Arcane's execute is a real threat now as well thanks to
Arkanes Bombardement and the value we get from
Arkanbeschuss in our single target rotation. Currently Arcane brings the 3 most valuable damage profiles you can have in a raid environment: burst, funnel, and execute. I would also be remiss if I did not call attention to the fact that in every way possible, Sunfury buffs everything useful about Arcane's damage profile.
Lastly, since the 10.1.5 rework, Mage's gained the spell
Massenbarriere which has been a huge buff for Arcane defensively. While
Lodernde Barriere and
Eisbarriere have their own independent benefits, neither is nearly as strong as the benefit provided from
Prismatische Barriere and this propagating to allies ends up being an extremely potent raid defensive. If you haven't saved lives as an Arcane Mage with this, I would urge you to think of those opportunities as they are not just gratifying but will literally save your raid wipes. All-in-all, Arcane has been designed as an extremely potent PvE spec and I would not be surprised if this remained true the rest of the season. At this point, I think Fire and Frost could do significantly more raw damage output and Arcane would still be a solid choice for people looking to push progression on the hardest content due to how well it is designed for raiding currently.