Thanks for all the hard work on the guide and the APL!
Could someone clarify a couple of points for me?
1. Should I save Presence of Mind for burn phases, or use it on-cooldown?
The APL seems to indicate that it'll delay a burn phase until it can start it with PoM when you have the tier 20 2-piece damage buff, but the conserve phase description indicates that you should use it on cooldown except when your next burn phase is 30+ seconds away. I guess if I follow the script the same way a computer would, I'd end up casting PoM exactly every 90 seconds when I do a burn phase, and lose out on some PoM casts over the course of the fight. (Unless I get lucky with T20 4-piece reductions and PoM comes off cooldown 30+ seconds away from a burn phase.. and then it sounds like it might delay the whole burn phase past when Arcane Power comes off cooldown)
Yes, burn phase will indeed be delayed to wait for PoM if you have T20. I think you're misreading the conserve phase though; you can use it if AP is still on cooldown for like 20+ seconds. It'll typically be back up before burn is ready.
2. When does the burn phase end? It looks in the script like it ends when you run out of mana, but it seems like in a lot of WarcraftLogs parses people just evocate at some random time ~20 seconds after starting their burn phase, even though they're still at 50% mana or more
Might be encounter-specific, i.e., avoid desyncing Evo from AP too much so you can ensure a tighter burn timing for some specific window.
3. How does the conserve phase work with the kilt legendary? Looking at WarcraftLogs parses and asking random mythic arcane mages, it sounds like they just burn their mana down to 50% every time, then enter a normal conserve phase where they repeatedly build to 4 arcane charges and arcane barrage until Arcane Power comes off cooldown
Conserve phase is exactly the same. Only differences I found so far: during RoP you can Arcane Explosion to about 60% mana before Barrage, and Arcane Blast indefinitely.
4. What's the optimal AoE DPS rotation for the new arcane shoulders? (They have a 10% chance to shoot a free Arcane Orb per Arcane Charge consumed by Arcane Barrage). I've been getting some 97th+ percentile parses for my gear level on Mistress Sassin' Me by building 4 Arcane Charges with Arcane Explosion and then just hitting Arcane Barrage immediately, but I don't think there's enough data to say that means it's a good strategy.
As of right now the only change with Mantle is to your burn phase, where you Barrage at 4 AC as long as there's more than 2 targets. The high chance of launching an Orb at 3+ targets ends up being a DPS increase.
The amount of Barrages actually prolongs your "burn" phase for like the whole fight. There may be a better way to use Mantle but I haven't found it yet.
[EDIT]Minor nitpick: What is the "lemon herb filet" food that the APL recommends? Is that some placeholder that gets swapped out for 500 int food? WoWhead seems to imply that it's food that gives you a straight up 1% versatility, which I guess would be 350ish versatility rating ?
Yeah, it's literally 1% Versatility. It doesn't add to your rating afaik but does increase the percentage.