Okay looking over things. Right now it's just a warlock with renamed abilities.

Archon's Sight doesn't make sense. Archons can't see in magical darkness; Devils on the other hand can see perfectly fine in magical darkness without limit (hence Devil's Sight). It should probably be completely replaced.

Celestial Presence again seems diabolic and not heavenly in the least. Archons are intimidating and excellent diplomats so those two bonuses should stay, but Bluff? I'd say swap it for Sense Motive as it fits the fluff closer.

Summon Swarm I'm on the fence about. Swarms of insects have a tendency to be connected to evil in modern ideas, but I can think of religious examples that connect them with Divine Wrath so I'd say it should stay.

Spider Walk ought to be replaced with a more celestial themed ability (again it's an ability associated with demonic possession and not angels).

Baleful Utterance you still have listed as using a word of Dark Speech which is an evil act and is the language of ultimate evil. Also it's a word of destruction and not really a Celestial ability.

Breath of Night at least needs a name change and Miasmic Cloud should probably be replaced with something more fitting of a celestial power source.

I'd say give them Walk Unseen since even though D&D celestials don't have it, it is a traditional power for angelic beings.

If you're giving them Summon Swarm give them Tenacious Plague as well, it's just an improved version of the former.

I'd also say they could have Devour Magic (maybe with a name change), or have the version from the Good aligned warlock PrC in Complete Mage.

Change Dark Foresight's name. It is heavenly insight forewarning you of the dangers in your path and allowing you to warn your friends. Except for the name it is completely power source neutral (at least as far as Celestial/Infernal goes).

Like Walk Unseen I'd say give them Retributive Invisibility.

Blast Shapes: Swap Eldritch for Celestial in their name.

Eldritch Essences (change to Celestial Essences):
Change Beshadowed Blast's name (the blinding effect is still completely appropriate).

Give them back Frightful Blast; Celestials can be scary when they're wrathful.

Force Blast is stronger than Vitriolic Blast but it is too weak for a Dark Invocation unless it has an unmarked rider effect (also why would force ignore SR?).

If you have Complete Mage it has some good invocations that could be adapted more easily.