Doomguard now benefits from haste value, but still doesnt benefit from haste multipliers. Except DI if you cast it onto him after he has been spawned. Base cast time of 3.0 seconds on Doombolt. Doesn't benefit from Lust before/after casting doomguard.
EDIT: added WoL info with doombolt casts from raid. Log taken from
here

[21:56:17.420] Doomguard begins to cast Doom Bolt
[21:56:20.298] Doomguard begins to cast Doom Bolt
[21:56:23.046] Doomguard begins to cast Doom Bolt
[21:56:26.200] Doomguard begins to cast Doom Bolt
[21:56:29.440] Doomguard begins to cast Doom Bolt
[21:56:32.295] Doomguard begins to cast Doom Bolt
[21:56:35.073] Doomguard begins to cast Doom Bolt
[21:56:38.256] Doomguard begins to cast Doom Bolt
[21:56:41.457] Doomguard begins to cast Doom Bolt
[21:56:44.309] Doomguard begins to cast Doom Bolt
[21:56:47.102] Doomguard begins to cast Doom Bolt
[21:56:50.298] Doomguard begins to cast Doom Bolt
[21:56:53.541] Doomguard begins to cast Doom Bolt
[21:56:56.750] Doomguard begins to cast Doom Bolt
[21:56:59.959] Doomguard begins to cast Doom Bolt
[21:57:03.168] Doomguard begins to cast Doom Bolt
[21:57:06.022] Doomguard begins to cast Doom Bolt
[21:57:08.803] Doomguard begins to cast Doom Bolt
[21:57:12.001] Doomguard begins to cast Doom Bolt
[21:57:15.215] Doomguard begins to cast Doom Bolt
[21:57:18.073] Doomguard begins to cast Doom Bolt
[21:57:20.872] Doomguard begins to cast Doom Bolt
[21:57:24.082] Doomguard begins to cast Doom Bolt
[21:57:27.272] Doomguard begins to cast Doom Bolt
[21:57:30.187] Doomguard begins to cast Doom Bolt
[21:57:32.896] Doomguard begins to cast Doom Bolt
[21:57:36.106] Doomguard begins to cast Doom Bolt
[21:57:39.320] Doomguard begins to cast Doom Bolt
First Doomguard is summoned while under the LFR IotCM, pushing my haste to 4752.
http://img41.imageshack.us/img41/730...2211160524.jpg

16:05:18> Sonicator gains Sonicator's Velocity.
16:05:23> Doomguard gains Doomguard's Demonic Pact.
16:05:25> Melee Target is afflicted by Sonicator's Bane of Doom.
16:05:29> Doomguard's Doom Bolt hits Melee Target for 1 Shadow.(28733 Overkill) (Critical)
16:05:31> Doomguard's Doom Bolt hits Melee Target for 262 Shadow.(14168 Overkill)
16:05:33> Doomguard's Doom Bolt hits Melee Target for 1 Shadow.(14423 Overkill)
16:05:36> Doomguard's Doom Bolt hits Melee Target for 1 Shadow.(28940 Overkill) (Critical)
16:05:38> Sonicator's Velocity fades from Sonicator.
16:05:38> Doomguard's Doom Bolt hits Melee Target for 1 Shadow.(28735 Overkill) (Critical)
16:05:41> Doomguard's Doom Bolt hits Melee Target for 1 Shadow.(14439 Overkill)
16:05:43> Doomguard's Doom Bolt hits Melee Target for 262 Shadow.(14206 Overkill)
16:05:46> Doomguard's Doom Bolt hits Melee Target for 1 Shadow.(14546 Overkill)
16:05:48> Doomguard's Doom Bolt hits Melee Target for 262 Shadow.(14231 Overkill)
16:05:51> Doomguard's Doom Bolt hits Melee Target for 1 Shadow.(14451 Overkill)
16:05:53> Doomguard's Doom Bolt hits Melee Target for 262 Shadow.(14196 Overkill)
16:05:56> Doomguard's Doom Bolt hits Melee Target for 1 Shadow.(28784 Overkill) (Critical)
16:05:58> Doomguard's Doom Bolt hits Melee Target for 261 Shadow.(14254 Overkill)
16:06:00> Doomguard's Doom Bolt hits Melee Target for 1 Shadow.(14417 Overkill)
16:06:03> Doomguard's Doom Bolt hits Melee Target for 262 Shadow.(14216 Overkill)
16:06:05> Doomguard's Doom Bolt hits Melee Target for 1 Shadow.(28738 Overkill) (Critical)
16:06:08> Doomguard's Doom Bolt hits Melee Target for 261 Shadow.(14149 Overkill)
16:06:10> Doomguard's Doom Bolt hits Melee Target for 1 Shadow.(14511 Overkill)
16:06:12> Doomguard's Doom Bolt hits Melee Target for 1 Shadow.(14412 Overkill)
16:06:15> Doomguard's Doom Bolt hits Melee Target for 262 Shadow.(14143 Overkill)
16:06:17> Doomguard's Doom Bolt hits Melee Target for 1 Shadow.(28963 Overkill) (Critical)
16:06:20> Doomguard's Doom Bolt hits Melee Target for 262 Shadow.(14189 Overkill)
16:06:22> Doomguard's Doom Bolt hits Melee Target for 1 Shadow.(14468 Overkill)
16:06:24> Doomguard's Doom Bolt hits Melee Target for 261 Shadow.(14195 Overkill)
16:06:27> Doomguard's Doom Bolt hits Melee Target for 1 Shadow.(28751 Overkill) (Critical)
16:06:29> Doomguard's Demonic Pact fades from Doomguard.
16:06:29> Doomguard died.
Second one with 0 haste rating.
http://img515.imageshack.us/img515/9...2211162201.jpg

16:22:00> Melee Target is afflicted by Sonicator's Bane of Doom.
16:22:04> Doomguard gains Doomguard's Demonic Pact.
16:22:04> Akinzeras's Demonic Pact fades from Sonicator.
16:22:04> Sonicator gains Doomguard's Demonic Pact.
16:22:10> Doomguard's Doom Bolt hits Melee Target for 4312 Shadow.
16:22:13> Doomguard's Doom Bolt hits Melee Target for 4336 Shadow.
16:22:16> Doomguard's Doom Bolt hits Melee Target for 1 Shadow.(4278 Overkill)
16:22:20> Doomguard's Doom Bolt hits Melee Target for 262 Shadow.(4048 Overkill)
16:22:23> Doomguard's Doom Bolt hits Melee Target for 1 Shadow.(4295 Overkill)
16:22:26> Doomguard's Doom Bolt hits Melee Target for 261 Shadow.(4010 Overkill)
16:22:29> Doomguard's Doom Bolt hits Melee Target for 1 Shadow.(4364 Overkill)
16:22:33> Doomguard's Doom Bolt hits Melee Target for 1 Shadow.(4337 Overkill)
16:22:36> Doomguard's Doom Bolt hits Melee Target for 262 Shadow.(4103 Overkill)
16:22:39> Doomguard's Doom Bolt hits Melee Target for 1 Shadow.(4336 Overkill)
16:22:42> Doomguard's Doom Bolt hits Melee Target for 261 Shadow.(4025 Overkill)
16:22:45> Doomguard's Doom Bolt hits Melee Target for 262 Shadow.(4115 Overkill)
16:22:49> Doomguard's Doom Bolt hits Melee Target for 1 Shadow.(4338 Overkill)
16:22:52> Doomguard's Doom Bolt hits Melee Target for 261 Shadow.(4119 Overkill)
16:22:55> Doomguard's Doom Bolt hits Melee Target for 1 Shadow.(4383 Overkill)
16:22:58> Doomguard's Doom Bolt hits Melee Target for 261 Shadow.(4022 Overkill)
16:23:00> Sonicator's Bane of Doom dissipates from Melee Target.
16:23:02> Doomguard's Doom Bolt hits Melee Target for 262 Shadow.(4097 Overkill)
16:23:05> Doomguard's Doom Bolt hits Melee Target for 1 Shadow.(4368 Overkill)
16:23:08> Doomguard's Doom Bolt hits Melee Target for 261 Shadow.(8388 Overkill) (Critical)
16:23:09> Doomguard's Demonic Pact fades from Doomguard.
If you pet swap to Felhunter with Assist toggled (probably applies to other pets as well), while standing on top of your target so your pet instantly hits the enemy, he hasn't scaled to your spell power yet, thus doing minimal dmg with shadowbite (and normal melee as well).

16:35:08> Sonicator gains Sonicator's Soulburn.
16:35:09> Sonicator gains Sonicator's Power Torrent.
16:35:09> Sonicator gains Sonicator's Molten Core.
16:35:09> Akinzeras's Legion Strike dissipates from Melee Target.
16:35:09> Melee Target is afflicted by Akinzeras's Legion Strike.
16:35:09> Akinzeras's Legion Strike hits Melee Target for 1 Physical.(7276 Overkill)
16:35:09> Akinzeras's melee swing hits Melee Target for 1 Physical.(5843 Overkill) (Critical)
16:35:09> Sonicator's Soulburn fades from Sonicator.
16:35:10> Sloofum's melee swing hits Melee Target for 1 Physical.(906 Overkill)
16:35:10> Akinzeras gains Sonicator's Summoning Disorientation.
16:35:10> Sloofum's Demonic Pact is refreshed on Sloofum.
16:35:10> Sonicator gains Sloofum's Fel Intelligence.
16:35:10> Sonicator gains Sloofum's Soul Link.
16:35:10> Sloofum's Shadow Bite hits Melee Target for 1 Shadow.(853 Overkill)
16:35:10> Akinzeras's Soul Link fades from Sonicator.
16:35:10> Akinzeras's Demonic Pact fades from Sonicator.
16:35:10> Sonicator gains Sloofum's Demonic Pact.
16:35:10> Sloofum's Demonic Pact fades from Sonicator.
16:35:10> Sonicator gains Sloofum's Demonic Pact.
16:35:11> Melee Target suffers 1 Shadow damage from Sonicator's Corruption.(2653 Overkill)
16:35:11> Sloofum's melee swing hits Melee Target for 1 Physical.(2531 Overkill)
16:35:11> Sonicator's Shadowflame hits Melee Target for 1 Shadow.(2495 Overkill)
16:35:12> Melee Target is afflicted by Sonicator's Shadowflame.
16:35:13> Sloofum's melee swing hits Melee Target for 262 Physical.(2183 Overkill)
16:35:13> Melee Target suffers 1 Fire damage from Sonicator's Shadowflame.(3413 Overkill)
16:35:13> Melee Target suffers 1 Fire damage from Sonicator's Immolate.(3498 Overkill)
16:35:13> Melee Target suffers 1 Shadow damage from Sonicator's Corruption.(2652 Overkill)
16:35:14> Sonicator's Wrath of Tarecgosa hits Melee Target for 1 Arcane.(2652 Overkill)
16:35:15> Sloofum's melee swing hits Melee Target for 1 Physical.(2445 Overkill)
16:35:15> Melee Target suffers 1 Fire damage from Sonicator's Shadowflame.(3413 Overkill)
16:35:16> Melee Target suffers 1 Fire damage from Sonicator's Immolate.(3498 Overkill)
16:35:16> Melee Target suffers 1 Shadow damage from Sonicator's Corruption.(2653 Overkill)
16:35:16> Sloofum's Shadow Bite hits Melee Target for 1 Shadow.(30224 Overkill)
Also, it seems you can now put Portal on Cho'gal middle area. Forgot to take a screenshot. This might apply to Nefarian & other similar places where you previously couldn't put portal on. (Gunship in ICC comes to mind)