One tweak i would love to see them make to the Genie pact warlock is to add Planar Ally to the spell list - perhaps with a 'genie only' restriction. Maybe remove Phantasmal Killer, and even add a genie-only Planar Binding too? It's a fairly small modification, but it really helps emulate the old 2e Al-qadim feel a bit more, where being a sha'ir was as much about negotiation with genies as it was about blasting things. I'd also hope if they published this they'd add gen options as familiars for Chain pact warlocks too.
I do like this pact as a whole, but it really does expose the limitations of using the core warlock as the basis for subclasses. Fundamentally, the warlock is very often a vehicle for dishing out force damage via Eldritch Blast. Many of its invocations are directly tied to Eldritch Blast, and it's really hard to make a warlock that can carry its weight in the average party without Eldritch Blast and Agonizing Blast, at the very least.
(The blade pact hexblade is the exception that proves the rule - a whole new slate of invocations and spells had to be invented in order to make it viable, and even then most builds I've seen take Eldritch Blast for some ranged capability)
Surely an efreet-pacted Warlock would be throwing fire around rather than force, thematically? Well, Produce Flame is simply laughably weak when in comparison with Eldritch blast. Less damage, less range, no options for improving it via invocations, and a more easily resisted damage type. Same if you pact to a dao - i guess you start using Magic Stone? It actually does quite well early on, because it adds the casting stat to damage, but it simply doesn't scale at all. And - elephant in the room - you're not even going to be able to cast either of these in the first place without Pact of the Tome or Magical Initiate, because they're not on the warlock cantrip list.
I hope the designers will put some thought into addressing the tyranny of Eldritch Blast and making it possible to make a more thematic warlock. It's just such a mandatory choice for a warlock at the moment (unless you're intent on going full melee hexblade), and a mandatory choice is no choice at all. Even having some pacts modify the energy type that Eldritch blast puts out would be an improvement. Other than the Genie pacts dealing elemental damage, an Undying pact warlock that used a necrotic Eldritch Blast would seem a perfectly in-theme change.