Mace Specialization Science

Mace Specialization appears to give both of your weapons 15% Armor Penetration, if only one hand has a Mace equipped, leaving your other hand available to use whatever weapon type with supporting talents that you'd like. This is in contrast to both the tooltip, and how all the other weapon specialization talents function.

For some simulation results:

TLDR: 258 Mace MH + 258 Dagger OH gives you identical single target damage to regular BIS Axes, and beats Axes by 200-600+ DPS when casting Fan of Knives

Currently as of 8/15/2023 both the websim implementation and Simon's sheet support these findings. No need for special setups, they just work as it does in game.

Setup you want:

258 Mace Main Hand: Remorseless / Cudgel of the Damned
258 Fast Dagger Off Hand: Steel Bladebreaker / Stygian Bladebreaker
A talent set up like these: Single Target, Fan of Knives Specialization. These trees only differ by trading points in CQC for Aggression, where on full Fan fights you don't Sinister Strike for Aggression talents.

Results you get:

You can get around a 250 dps increase over standard bis setups on 2 target Fan cleave
You can get around a 550 dps increase over standard bis setups on 3 target Fan cleave
All of this at either a tiny single target dps loss, or a tiny single target dps gain
Either identical or slightly improved 2 target Blade Flurry cleave
By swapping your talent setups out of Aggression and into Close Quarters Combat, as linked above, you can lose 100 single target dps for about 50 - 200 dps on 2 and 3 target Fan cleave respectively

This is due to not only that ARP is a great stat on cleave, but your Dagger off hand gets that nice Fan of Knives damage multiplier - and Hack and Slash already has a bit of diminishing returns when you hit so many times in sequence due to its short internal cooldown.

These values are generalized P3 BIS setups with Runestone/Comet, and I believe are generally correct for most setups. You probably should have Runestone equipped most of the time even with a Death's Verdict, but if you don't, the Mace Spec gets about 20 dps worse. The findings are essentially identical while Exposing.

This was tested on 8/2/2023 on a live client, detailed here. To summarize, Mace Specialization was talented, and no maces were equipped and a white, no stat off hand. Sinister Strike damage recorded. Swap weapons to a white, no stat, mace off hand, and record Sinister Strike damage. We'd expect about a 5-6% physical damage gain from 15% Armor Penetration depending on player ARP and target armor, and the data observed about a 5% damage gain. Other independent tests on real mobs, namely the invulnerable mob in Blasted Lands, have found similar results.

Other setups we tried that just aren't as good

There isn't really a good off hand Mace with a fast weapon speed, this tier or any really, so you kinda have to use only a Main Hand
Other weapon setups with Hack and Slash off hands tend to fall apart when trying to go down the Combat talent tree, you have to give up some key talents to get down to the lower tier which holds Mace and Hack spec.
Swapping all gems from Attack Power to Armor Penetration. This is about the same as it was for regular Hack and Slash - it was about a 0.5% loss on extended single target, but a 0.5% gain on a Blade Flurry flight like Twin Valkyr, and with Maces the single target loss shrinks down to about 0.25% and the gain stays about the same. Probably the same value proposition - if most of your fights deal damage with Blade Flurry and value your add damage equally to single target damage, then ARP gems are probably the play. If your team has a ton of passive cleave and the adds in your encounters are simply not threatening or important damage, then AP gems keep you doing important damage.

Conclusion

This is still a new finding, so there is still room for further refinement of strategy and mechanics, as well as time for parts of this mechanic to be found out as different than we currently understand. Or for it to be patched. Feel free to comment below with your findings.

where-fore / rogue-wotlk