Ok, some final feedback on this set. I tried bringing him to Ant's DM event yesterday. Couple things I noticed, Warlocks are slow to cast without any Metas, the Special ability pet we get, wont jump in and fight half the time. The feats he has look great, but honestly, compared to the pet on the Eternal Robes of Darkness, his is very under par. I suggest removing Epic Hellball, which I have never seen him cast, give him Quake Shock and possibly an Aura of some sorts to help him keep some mobs on him. His hit points even at ER5 are half of what the Eternal Robes pet has and he hits for less damage. On his character sheet, it shows him lvl 78, but when inspected by anyone else it only shows him as class lvl 20.
I eventually changed characters for the 2nd half just because everything was immune to any of the special affects warlocks get. Through the storyline they are fun to play, but a lot of work is going to need to be done to make them viable for event stuff. Not trying to sound negative, and will try to give some suggestions to help without making them to overpowered. Even with Doom Blast, all the mobs have evasion, improved evasion, epic dodge, just to hard to hit.
Not sure if it could be done, but possibly making Eldritch Chain hit the same mob multiple times, even if there is only one mob there and have the set increase Ranged Touch Attack to help it hit more effectively. Doing this, would have to make each hit drop in damage by a certain percentage, or could be way overpowered. This at least might bypass some of the evasion, improved evasion and epic dodge problems. As for the special affects working, I even have harsh caster on but when mobs are immune, they are immune. Bypassing spell resistances doesn't affect that as far as I know. Maybe a special feat similar to Harsh Caster (Harsh Invoker!) that would let the Warlock bypass immunities based on their caster level or spell DC.
Another suggestion would be to have the set increase how many invocations we can have. Its a 6 set piece, maybe +1 bonus to all spell known with 3-5 pieces and +2 bonus to spells known with the full set.
If we do get Empower and Maximize blast put on the set, having them be cooldown based instead of 3 uses per rest would be a nice benefit (30 sec cooldown). Quicken spell would be nice, for all spells but blasts/shapes.
Possibly adding an Epic Eldritch Blast 1d6 for each set piece equipped. That would open up 6 feat slots for a warlock trying to go for full damage if they were wearing the full set. This would let them pick up Epic Fiendish Resiliences or some Epic spells or whatever else they needed. Survivabilty wise, possibly adding a damage shield to Retributive Invisibility that does 10-20% of the warlocks blast damage or increasing it to 60% conceal.
Would also be nice to see a lot more of the spells they have get bonuses to something damage or affect wise based on ER level. As stated above (Harsh Invoker) a 15% chance per ER lvl to bypass a mobs immunities. That would give them a 75% chance to stun, fear, fright whatever anything if they succeed in a DC check and they are ER5. Also Entropic Warding, once you get Retributive Invisibility, it becomes useless. Maybe make it add 12% conceal to Arrows per ER level, that would give it an 80% chance to not get hit by arrows.
That's all I can think of for now. I'm sure everyone that has played has some ideas that could help. Thanks for the work you guys are doing!