First. Welcome to the PRC (and specifically the build boards).
You may consider the following.
Path of Shadow. Unlimited insta-heal. Also, if you max out UMD at L40 as a WL, you can cast almost any scroll in the game, so that's a massive bonus. At one point, Natural Spell was supposed to allow spell casting in shifted form. IDK if invokes were treated the same. Wall of Perilous Flame was nice against the non-SR crowd. Chill Tent would root them in place, Wall of PF would fry crowds nicely. Devour Magic was the Dispel Magic equivalent, but I never used it.
I tried Eldritch Doom & split ray feats, but it didn't work. I don't recall ED working as an AoE either. Wep Focus ray was supposed to work for EBlast. I think Dex is the primary stat for the touch attack, so you may miss a fair amount with a dump stat there.
Practiced Invoker WL gives +4 Caster Level.
Since BG gives Turning, Div Might / Shield can really add damage + AC.
IIRC, Extend spell was supposed to work on invokes, so Extend Spell would be something to get for Chilling Tent & similar. Don't recall if the Spell Pen stacks boosted invoker level or not.
I use Path of Shadow in almost every warlock build, you just don't really need it in this one with utterdark doom healing. It is incredibly good (and SUPER convenient) though! I found out not too long ago you can cast it, heal your whole party, but not choose to teleport... Cheese, but incredible. Also, the Chilling Tentacles script was bugged, so I fixed it and it is now in the alpha. Tentacles are so good now after the update, best single invocation/spell/SLA/etc in the game now IMO.
UMD is one of the greatest benefits of the Warlock class. So versatile for spells and equips. And with Imbue Item, it is a cheese engine.
Invocations follow the same rules as spells in shifted form, but most of the great PnP Shifter forms don't need Natural Spell to cast spells, they can already do it.
Doom is definitely AoE, massive AoE with sculptor. Weapon Focus (Ray) works with EB and DEX does help, but I have like 100 hours in this build or very close builds, and neither is really needed in my experience. If you can't hit a baddie's AC with Chain, switch to Cone or Doom and don't worry about needing to hit - it is very rare that an enemy has both high AC and evasion.
Practiced Invoker went bye-bye. It isn't a PnP feat so it got culled.
The turning feats are nice, but NOTHING compares to Lolth's Meat for adding divine damage. On average, every single attack I make has about 20-30 extra divine damage from Lolth's Meat. And it also boosts your saves and attack as well!
Spell penetration works with invocations but not extend. As a melee warlock build, this one doesn't grab penetration. If I need to EB something with SR, I switch to vitriolic and bypass it altogether.