Mark of Defiance would be amazing but it does have some sort of hidden cooldown. How long, I have no idea. If it's not that long, it might not be so bad.

It's tested and confirmed to stack on each missile. The game isn't making a distinction between on spell cast and on spell hit for arcane missiles (normally the only distinction would be with AoE abilities anyways). Each missile counts as a cast and according to some, the initial cast also counts as a cast meaning 6 "casts" per 5 seconds.

Pretty sure the prohibition is on mana-free abilities like changing paladin Auras or casting Find Minerals. Shamans using Totem of the Maelstrom cast (talented) Healing Wave r1 for free (no mana expenditure) and it procs the Pendant.

I stand corrected then. Gotta get me a Violet Eye, clearly...

I'm not sure if the proc is on-hit, but even if it is, the Blade of Wizardry has a hidden internal cooldown and thus won't synergise particularly well with AM spam (unlike TLC/Ashtongue etc).

If the cooldown is 30 seconds (as listed on wowhead) and it procced the second the internal cooldown expired it would be equivalent to a flat (280 * 6 / 30) = 56 haste rating or 3.6% haste using the new conversion ratio.

My gut feeling is that this wouldn't be worth the +dmg/stats loss from either the Merciless Gladiator or raiding one-handers, but YMMV.

Has anyone information if the procs on Circlet of Arcane Might and Coronet of the Verdant Flame will be affected by each missile in the next patch? Right now they are terrible items.

I got the same question for the [Insightful Earthstorm Diamond], would be quite nice to have a ~10% chance of getting 300 mana back every Arcane Missile spell. Just interested

Extra mana with an Arcane spec should be converted into extra damage ofcourse.
I won't be using [Mystical Skyfire Diamond] when I get my hands on 2 T5 and spec Arcane, in my opinion it only shines with massive procs and haste rating while spamming Arcane Missiles.
If [Insightful Earthstorm Diamond] works the way it should, thus proccing off every missile, I will maybe try it out. There would be quite some chance it procs during a AB-AB-AM-Scorch rotation (9 on spellcast checks).

Ok before this turns into a mess, [Insightful Earthstorm Diamond] is a terrible metagem for like pretty much every possible class.

2% chance per spell cast to restore 300 mana.

Assuming you can get 6 procs per AM (derived from PTR proc rates on MSD), that means a bit below 12% chance to proc 300 mana / AM. Let's be generous and assume 12% proc rate per AM. That means you get, on average 300 * 0.12 = 36 mana / AM.

Under the best case scenario, its not usable. Please let it die.

My bad; I thought the poster was quoting a 10% chance as 10% per missile, so 50% per cast. As it's just 2% per missile (10% per cast), then yes, it's downright horrible.

So the test servers just came back up with the patch to make MSD buffs last 10 seconds and I can confirm that the impossible has happened: You can chain 4-5 AM casts off a single MSD proc. It's fairly insane: *BUT* there's a possibillity of a hidden cooldown on the MSD now. I need to get a much larger sample size before I could say that with any certainy and my initial test may have just been unlucky (sample size was small enough that luck could have done it).

I'm going to downrank my AM to rank 3 so i can do a much larger sample size and see if I can confirm chain procs are still alive and kicking.

Edit: Tested and confirmed there is NO hidden cooldown. My intial test was just too small of a sample size. I was chain casting rank 3 AM at double speed for 30 seconds in a row. The DPS on rank 3 spam is up a significant bit becuase of this.

So, long post short, Everything we thought couldnt' happen has happened. MSD lasts 10 seconds and is not consumed by AM, 3-5 casts per MSD proc is possible which can indeed lead to semi-frequent chain proccing. Combined with a lightning capacitor, it is, in a word (or two), absolutely insane.