I'm arriving a bit late at the thread, but there's lots of interesting stuff to reply to, so I'll quote generously. Beware the
wall of text...
To make this (barely) coherent, I've ordered conversations by topic rather than chronologically: first the warlock's low damage, then the Starlock's terrible AC, and finally the ability score distribution.
Issue 1 - Low damage
(...) a feat to bump up their damage from a d6's to d8's
would clash with several magical items (...) the simplest approach is to give a fixed damage bonus.
Dooming Curse (...)
This works, but is slightly weak. Warlocks need strong damage boosts. I'd give it something extra, like this:
Agonizing Curse
Requirements: Warlock, Warlock's Curse class feature
Benefit: Increase your Warlock's Curse damage by 1 per curse damage die.
When you score a critical hit against a cursed enemy, you deal additional damage equal to your Warlock's Curse extra damage. (This extra damage is not automatically maximum damage)
Add {ability} modifier damage
That, on the other hand, would be too strong. They would be getting as much damage as sorcerers, plus the curse bonus.
Change curse (...) so they can do AoE more respectably like the sorcerer.
I like AoE striking as a sorcerer niche. Warlocks seem a lot more focused towards single target attacks, anyway.
Prime Shot giving +5 damage at 11th level makes a big difference. Could make that part of the base class or a heroic feat.
Granting extra damage through Prime Shot is a great solution, and it really helps to make the feature more relevant. However, I always thought the Called Shot feat to be rather overpowered (+5 damage!), and moving it to heroic without changing the amount should be out of the question. A more reasonable version would be:
Recalled Shot
Prerequisite: Prime Shot Class feature
Benefit: Whenever you successfully hit a target against whom you received your Prime Shot bonus, your attack deals an additional 2 damage. Increase this extra damage to 3 at 11th level, and 4 at 21st level.
warlocks are behind sorcerors in single target damage by precisely the amount that giving them a d6->d8 striker feat would fix.
If that is true, the feat wouldn't solve this difference unless you gave it for free, since a sorcerer can spend a feat (say, Arcane Spellfury) to boost his attacks, too. I'm afraid that the only practical solution would be making above-average damage enhancing feats that were exclusive to Warlocks. Note that Called Shot and the variant shown above can actually be used by Rangers. You don't want more overpowered feats that a Ranger can use.
I would rather go with the following feats
Resonating Curse.
Repeated Curse.
Resonating Curse is a great idea, and I'll try to include it in my games when I get a chance. Repeated Curse I don't like so much, since improving warlock AoE gets too much in the Sorcerer's field to my tastes. I'd rather let warlocks have the edge on single targets.
It's a lot more than just the warlock lacking a feat. It's a core class feature and multiple feats.
I don't think that's too fair to the warlock. What they are really missing are a couple of damage points. They have plenty of cool, useful features otherwise. And their defenses, apart from the Starlock disaster, are good or even great. Comparisons with Sorcerers tend to miss the fact that, regarding defenses, Int-using Warlocks start a feat ahead (Leather Prof.) and are otherwise around 1 point higher (Shadow Walk being worth 2 points, and Sorcerer features a bit less than 1).
Issue 2- Starlock defense
the star warlock should get chain proficiency
chainmal alone is probably also insufficient(...)
Hadars Armor
Actually, chainmail is decent enough, for a class that isn't supposed to get into melee. Specially if you take into account the 2 extra points from Shadow Walk's concealment... I understand some player's desire to achieve great defenses, but I'd say upgrading from chain is far from mandatory. Other than that, I agree that starlock defense sucks, and it would need a little improvement. Chain proficiency is a solution that works within existing rules, but since we're houseruling... why not give them good defense in light armor? The way I see it, heavily armored warlocks hardly fit the class' flavor, anyway. Other possible feat that fixes defenses and gives a little extra would be:
Unnatural Celerity
Requirements: Warlock, Eldritch Pact class feature.
Benefit: While you are not wearing heavy armor, you can use the lowest of your Constitution and Charisma modifier in place of your Dexterity or Intelligence modifier to determine your AC and Reflex defense. In addition, you can use this modifier in place of your Dexterity modifier to determine your initiative
Issue 3 - Starlock ability scores
(...)focus entirely on one ability score for attacks
Star Channeler]
I've inverted the warlock's primary and secondary stats, making it an 'A' class instead of a 'V'
These solutions do their job, though I don't like intelligence as main score, for this class. It does have important mechanical advantages, but I don't think it fits. Then again, if you choose either Con or Cha as main, and use the other two as secondary, you're facing again one build with lousy AC.
One interesting, though difficult to implement, approach to solving MAD is what they achieved with Paladins in Divine Power: creating a viable MAD build. In the Paladin's case, the feat Mighty Challenge is a great reward for having high scores in both Strength and Charisma, resulting in monstruous Divine Challenge damage. Maybe we could do something similar with Warlocks? Making starlocks feel good about mixing Charisma and Constitution powers...
The following feat is wordy, and stronger than most, but it also has strict requirements regarding power selection and use, and I think it could be quite fun:
Celestial Madness
Requirements: Warlock
Benefit:When you use a warlock attack power, if you use Charisma for the attack roll you gain a +1 bonus to attack rolls using Constitution and a +2 bonus to subsequent damage rolls until the end of your next turn.
When you use a warlock attack power, if you use Constitution for the attack roll you gain a +1 bonus to attack rolls using Charisma and a +2 bonus to subsequent damage rolls until the end of your next turn.
Increase the damage bonus to +3 at 11th level, and +4 at 21st level
