Spells that do something for battle, surely. Perhaps illusion or escape spells. For a warlock to take a spell, it's gotta either scale or be almost always relevant. Those up there are some of the most situational spells in D&D. Only Color Spray is good for battle and it scales terribly.
Warlocks are pretty much always good at diplomacy. They have charisma focus and their goal is pumping it high as soon as possible. Anyway, even intrigue-focused subclasses like Glamor and Whispers Bard and Inquisitive and Mastermind Rogue have something for combat.
Advantage against charm effects is literally weaker than the elf racial feature. You should just give immunity up front. And advantage against fear is the halfling racial feature. Just give immunity.
So those are the only combat buffs in there, anti-charm and anti-fear. Pretending you're charmed or frightened while you're not has no benefit. If you act like it, isn't it as good as someone having charmed you anyway? And if you don't, that little extra feature does nothing. Anyone can pretend to be charmed or frightened anyway, all they need is a perform check. From what I see, the charm and fear spells don't even tell you whether the effect succeeded or failed.
A much more fitting effect would be turning the effect back on the caster, though Archfey already has something like that. Maybe you could broaden the scale of conditions it'd work against. Advantage in mental saves in general would be fitting.
How about instead of diplomancer, you have it play tricks on the enemy?
About the level 6 feature, rolling an 11 isn't a very impressive thing to do once per rest. Rogues can auto-succeed on things by level 11. And Glibness is nice and all but it still doesn't help in combat. It also renders the level 6 feature irrelevant.
Hrm. I'm not sure you've ever been with a proper diplomancer, but as far as tactical action drama you're right and this will definitely not be as exciting as the other warlock patrons. So let's start with the spells! These are still generally in the vein of trickery I think, although I wouldn't count out access to some of the original list (very specifically on a short rest recharging basis--it isn't the same as having more oomph in battle, but it's lateral power that could definitely be very dangerous in the right hands).
1st | faerie fire, silent image |
2nd | arcanist's magic aura, blur |
3rd | bestow curse, clairvoyance |
4th | conjure woodland beings, polymorph |
5th | conjure elemental, mislead |
I'm not sure if they've addressed it on Sage Advice but most spells that inflict a charm or fear effect are concentration. On that basis I think you'd have to know whether or not your magic has effected a creature. Maybe not so for things with passive fear auras and what have you? Point taken though so let's wrap them into one.
Trickster’s Mind
At 1st level, you have advantage on saving throws against being charmed or frightened. When you successfully resist one of these conditions, until you act otherwise the creature that would have charmed or frightened you believes it has done so.
Gifted Storyteller can do with some love too--let's say more uses. I like it and the ability to avoid magical compulsion to tell the truth is really important for an archetype about trickery.
Gifted Storyteller
At 6th level, no matter what you say, magic that would determine if you are telling the truth cannot tell whether or not you are lying. In addition, when you make a Charisma (Deception or Persuasion) check, you can replace the number you roll with 8 + your proficiency bonus. Once you have used this feature a number of times equal to your Charisma modifier, you must finish a short or long rest before you can use this feature again.
I'm going to leave
glibness as is too for the same reasons, but that leaves 10th level just hanging around. How about this? I can see it being pretty powerful but an opponent will need to be pretty dumb to keep failing at it (the Tarrasque would probably smack itself a few times before figuring it out).
Clever Steps
At 10th level, you can cause a creature taking a wild swing at you to connect with another enemy or even themselves. Once per turn, when you would be hit by an opportunity attack you can force the attacker to make an Intelligence saving throw against your spell save DC. On a failed save, the creature's opportunity attack targets itself or an adjacent creature of your choice, and the creature has advantage on its attack roll. On a successful save, the creature has disadvantage on its opportunity attack against you.
Thanks for posting!