Everything that has been done so far for the Warlocks has been awesome and I appreciate all of it. Especially the Pit Fiend, I am a huge fan of his and will always back him up when someone tries to say that the Lich is better. I haven't actually tried the other option available at level 12 yet even though that was what I had first planned for my Warlock, I just became too obsessed with the Pit Fiend to really try the other option. Having options however, is something I absolutely love, so the mere fact that it exists is something I endorse whole-heartedly. I also love the improvements to Word of Changing, even though it gets me killed more often than not due to my inability to drink potions while using it. I'll happily take a few extra deaths if I get to be an otherwise functional Demon while doing so. I also appreciate the combination of all of the little tweaks to their AC and such, designed to make them a viable option in the first place.
Now on to the actual suggestions:
Uncanny Dodge: Warlocks are already locked in to taking Hellfire Warlock as one of their classes. Having to throw a Cleric dip (or some other dip to get UD) in the mix locks up a third class, only leaving a single class for warlocks to play with. The more classes one is forced to take in order to fill that classes minimum requirements to function, the less build diversity is possible. Build diversity should be promoted, so I think Warlocks should get Uncanny Dodge in their natural level progression, just like what was done for Monks.
The Greater Chasuble of Fell Power: This amulet is of key importance for the Warlock, to the same extent that a a Fighter likes to collect damage bonuses on their weapons. But due to how Kaedrin scripted the thing (and how RoT needs to flag items as ER 1 only), if you take it to a forge higher than the Hell Forge, that property breaks. It also doesn't carry over when using Word of Changing.
My proposed solution is to add that enchant as an option for amulets at the Underdark Forge, or if it is easier: just have that Forge apply the Greater Chasuble's Flag to every single amulet that gets forged there. Giving the enchantment for free would just save a few gold and gold is meaningless anyway. This would also alleviate the issue of having to choose between the Chasuble and their Set Item Amulet. If for whatever reason this isn't implemented, then another possible solution would be to add a scaling Natural Armor buff to one of the Warlock's spells, so that he can achieve 12 Natural Armor while wearing a less enchanted Chasuble.
As for it not carrying over to Word of Changing, I don't know how easily that could be fixed due to the weird way that the Chasuble is scripted. If it can be done however, it really should be fixed, especially considering my next two suggestions are to expand that weird Chasuble script, so they would be broken while using word of Changing too.
The Set Items: Having to choose between the Chasuble and the Set Amulet really contradicts good set design. No other class's Set Items actively reduces their damage output like the Warlock's does and this really needs to be fixed. The Amulet Set Item could just be moved to the Cloak slot, but that would remove access to the Improved Combat Expertise Cloaks, which I am sure a lot of people would complain about. The solution: Add Improved Combat Expertise to it too! Or just add the Greater Chasuble's +damage flag to the Set Item Amulet, or make that property forgeable at the Underdark Forge.
The other issue regarding the Set Items is one I am less qualified to talk about as I haven't experienced it myself, but everyone else complains about it so I would be doing them a disservice if I did not mention it: the damage set bonus. Such a bonus has no value to a Warlock which uses its Eldritch Blasts as damage. If it can use whatever system Kaedrin used for the Chasuble to add that damage to the Eldritch Blast (or even a reduced bonus to the EB), that would obviously be much, much better. But for all I know, that damage already applies to the EB and everyone (like me now) that has been complaining about it is very uninformed.
Legendary Metals: I'm happy enough to stick these things on my armor if necessary, but if the above two suggestions are taken in to account, making the Chasuble's flag craftable and perhaps even extending it to include the damage bonus of the Warlock's Set Items, then that same system could be adapted to include the damage bonuses of the Legendary Metals. Forge them on the amulet and get their damage bonuses added to your Eldritch Blast. If the system Kaedrin used to add to EB damage on the Chasuble isn't elaborate enough to add varying damage types, just adding basic EB damage like the Chasuable does would be a fair compromise. Or just ignore this suggestion entirely as it is the one I am least enthusiastic about - it is the one suggestion that wouldn't just bring Warlocks in line with the other casters, but actually push them out ahead, which is not something that should be encouraged. It would be cool though for Warlocks to be able to use their Legendary Metals offensively like the weapon users do and the system seems to already exist to make that possible, I'd just like to see the other casters receive the ability to use their Legendary Metals offensively too if it were to happen.
Damage Scaling: This is a lot more controversial, but Eldritch Blast just doesn't keep up with damage. It scales every second Caster Level while the offensive spells of every other caster scale every level. This forces the Warlock to get his hands on as many Epic Eldritch Blast feats as possible in an impossible-to-achieve hope of closing the gap. Even if they got their hands on all 10 of the feats, that just gives a level 40 character 40 1:1 levels worth of scaling, which is something the other casters get without investing a massive 10 Epic Feats in to. Some would argue that +50% damage from Eldritch Master and +30% damage from Hellfire Warlock is enough to close the gap, but those bonuses don't close anything as they just keep parity with the +50% Empower, +20% Epic Explosive Damage, the Inexorabilis Rune, as well as whatever damage benefits they get from their chosen PRCs.
The solution is simple: give Warlocks the same 1 die 1 level scaling that all of the other casters get. That however would cause issues when stacked with the Epic Eldritch Blast Feats as well as the multiple attacks of Eldritch Glaive. Simply getting rid of the Epic Eldritch Blast feats is an easy fix to the former issue, but I'm sure there would be plenty of complaints if Eldritch Glaive went away in the same manner. I however would be perfectly okay with throwing away Glaive if it meant the rest of the class actually kept up as it should. I'd rather have a fully functional class without Glaive, than a class that was only really functional while using Glaive. However, if you want to keep Glaive while properly having the Warlock's damage scale as well as everyone else's, you can implement a more complicated script where the Eldritch Blast's base damage is divided by the number of attacks Glaive is making and only the extra damage of the Chasuble (and the Set Items, and the Legendary Metals if those suggestions are implemented) is added more than once per casting. That would still give Glaive a use, without it getting out of control on a properly scaled Warlock.
Imbue Item: This is more of a bug report than an actual suggestion, but that class feat doesn't actually work as described. I don't think it does much of anything, but making it so the 25% discount actually applies would be welcomed. While you are at it, you can add the Warlock to the list of classes (Bard/Rogue) that are capable of Class Emulation. Use Magic Device is supposed to be the Warlock's thing, even more-so than the two classes that do have Class emulation allowed. If any of the three should be capable of doing it, Warlock should absolutely be the one.