Haste works for all party members as well!
The one real difference is that you need to be somewhat near the party to add Haste to the party. For Flee the Scene you can be anywhere and everyone gets the effect.
I can understand it though in conjunction with armor (spell-failure) and not wanting to loose spells.
Excepting spell failure.. Sorcerers tend to have so many castings (especially with meta magic like extend and empower) that you aren't going to be persistently napping.
IMO the biggest difference in the spell grouping between Warlock and Sorcerer is Walk Unseen vs. Invisibility. Perform any action other than movement (or inventory swapping) with Invisibility and you loose invisibility. For Walk Unseen you remain invisible for many different actions (obviously excepting an attacking action). You could base an entire build around this particular difference. :mischief:
Marital Weapon Proficiency: Barbarians, fighters, paladins, rangers, swashbucklers, dwarven defenders, BLACKGUARDS, duelists and arcane archers get it. Clerics also get it depending on the domain and God chosen. Working-in 2 levels of Blackguard nets you another Charisma modifier.

A third and fourth can provide you with Divine Shield and Divine Might if desired.
Yeah, Kaedrins is overpowered for several of the classes - DON'T CHOOSE THEM.

(..I know, that Swiftblade is MIGHTY tempting!

)
Sticking to your basic plan though I'd do it something like this:
Wood Elf: 17/14/12/10/12/14 (always increase Strength)
Evil (chaotic, neutral, or lawful)
2 Warlock
2 Sorcerer
Warlock
Sorcerer
Warlock
Sorcerer
Warlock
Warlock
Sorcerer
Sorcerer
Blackguard
Blackguard
Blackguard
EK, EK, EK, EK, EK
Feats (in order): (Background: Veteran), Luck of Heroes, Power Attack, Cleave, Combat Casting, Brew Potion, Divine Might or Divine Shield, Craftwand.
Basically interleave Warlock + Sorcerer to avoid penalties and start getting good with buffs at easier lower levels while having a decent Attack Bonus and Cleaves.
Invocations: Darkness, Hideous Blow, The Dark One's Own Luck, and finally Walk Unseen.
That gives you the counter offensive of Darkness from the start (and improves latter with Blindsight) - which should be a good "edge" throughout the game. Saves aren't terribly important early on so we can delay the Dark Ones Own Luck until your 3rd and final Least Invocation.
Hideous Blow plus this mod should give you some additional leverage with your Eldritch blast (..not a lot, but a little at least):
http://nwvault.ign.com/View.php?view=NW ... ail&id=320
or this one with some more functionality and bit of "cheese":
http://nwvault.ign.com/View.php?view=NW ... ail&id=320
I "pushed" the build once at level 10 to accelerate the selection of Walk Unseen and your BAB. At level 10, and ONLY level 10, you will have a 20% exp. penalty.
The real "magic" of the build is Walk Unseen with potions (and later wands). Walk Unseen, though susceptible to spell failure, can be cast infinity. Potions and Wands don't have spell failure. Basically you can motor about unseen in full plate with a shield and still do most "casting" - if you wanted to.
Shields in particular are nice to have.. NOT because of the +1 or +2 Shield bonus (though that is nice), but rather the enchantment potential.

PLUS, Mithral shields you can use (Light or Heavy) without any spell failure penalty.. OR take a 5% penalty later on with Shield of the Void. You can use them at level 13.. which is about when your party can start making better enchantments.
The one thing you give up is Flee the Scene (because it would require 2 more Warlock levels and it isn't a cost effective trade, especially not because you'll have access to Haste). Blindfight is also missing, but it really isn't needed in this game (..I've tested this out and there are *very* few concealed opponents, plus you'll have access to Blindsight). Finally, skills are seriously lacking and you'll need to plow 10 points into Hide (for a net of 5) before level 13.
Spells (in order):
1st level: Enlarge Person, Protection from Alignment, Nightshield, Grease, Truestrike.
2nd level: Mirror Image (or Fireburst*), Blindsight, Ghostly Visage, Gust of Wind.
3rd level: Haste, Improved Mage Armor (or Heroism*), Flame Arrow.
4th level: Orb of Sound and Evards.
*Several spells are apparently bugged with respect to potion brewing. NEITHER Mirror Image nor Improved Mage Armor create their respective potions. However Fireburst creates Mirror Image and Heroism creates Improved Mage Armor. I guess it depends on how you want to build it for which you would select. The nice thing is that both of these spells are long duration from a bottle, but it would delay the use of Mirror Image until character level 12. I'd probably stay with the Mirror Image spell but select Heroism instead of Improved Mage Armor (basically getting a two-for-one bonus).
Protection from Alignment, True Strike, and Ghostly Visage ALL produce potions, and all the potions have excellent durations (and are inexpensive).
Note that Blade of Fire is useless because of duration, but Enlarge Person adds as much average damage AND most of that damage is magical (non-resistible, unlike fire damage) - while also having a good duration. (..it also makes you more difficult to knockdown.)
Note that Flame Arrow via a wand is effectively 16d6 per casting, and doesn't require a touch attack calculation.