So last night I picked up Waistwrap of Infinity. "Why? It isn't very good." you ask? Well it isn't very good right now but A) It was going to rot anyway and B) I hear from Leiah(who at this very moment is facing down an Elemental Shaman firing squad...) that there will be some sort of change to Haste regarding instant cast spells.
Ultimately I'm taking a chance here, rolling the dice on a piece of loot that hinges on information I don't really even have knowledge of. I do, however, have a few ideas how such a change might go down:
1) Haste will lower the duration of the global cooldown for instants and perhaps allow cast time spells drop below the GCD. If Blizzard thinks they'd be giving us anything with this then they're sorely mistaken. Maybe Mages might appreciate it for Scorch, it might help Resto Druids a little, but if this is their idea of making Haste more appealing I'd change my opinion of Blizzard from "slow to react" to "out of touch with their game." I'm banking on this not being the answer, however as I do have more confidence in Blizzard than that.
2) Haste will increase the damage/healing of instant cast spells. IE 1% Haste would increase the damage or healing of Curse of Agony, Rejuvenation, Ice Lance, etc by 1%. This seems much more reasonable and is what I'm thinking Blizzard will do, however will simply result in my making a big fuss on the PTR forums to try to get #3...
3) Haste will increase the damage/healing of instant cast spells as well as the damage-over-time portions of cast-time spells. Haste as it would be in #2 would not effectively increase the DPS of Unstable Affliction, Immolate, and maybe Corruption(depending on how they code it...) Spells that are not chained back to back simply don't reap any real benefit from Haste. If you're going to re-apply a cast-time DoT you will simply cast it so it is applied right after it expires (regardless of cast time) for no Haste driven DPS gain. The goal, IMO is to have 1% haste increase the damage of all spells by 1%(minus an obvious increase in mana consumption) This includes increasing the cast speed of Nukes, the damage of all instant spells, *and* the damage of cast-time DoTs.
If #3 does indeed happen it will totally change how Shadowpriests, Affliction Locks, and Resto Druids gear for raids. It will make currently trashy epics like the aforementioned Waistwrap of Infinity, Nimble Thought craftable bracers/shoulders as well a some of the Resto Druid gear with all but wasted haste already on it. According to Leulier's Spreadsheet (with some tweaks) 1 Haste Rating would = 1 spell damage at ~1200 spell damage, though with haste costing more itemization points it would result in a much better itemization environment for raid DoTers and HoTers. We'd have options!
EDIT: 2 Threads discussing the incoming changes on Haste. AKA me bitching that it's not effecting DoTs in any significant manner and does nothing to aid Shadowpriest and Affliction Lock endgame raid itemization dilemma.