Chainmail? Damn. That actually is a shame. But it seems Divine characters always are about The Armor.
I dislike the fluff about Invokers being all old school, and all about Primordials vs. Gods; that's the first fluff I'd squash in my games. As I read though, I notice that the class has a warlock vibe to it, how close the individual is with the god. I could see this as the Divine version of the warlock, although I'm not sure how best to represent Invokers of the Fey, etc. It's easy for me to see specific ArchAngels giving Invokers power.
However, one thing is certaion: these guys scream Prophet, operating outside the church, with a direct link to their God.
I notice Channel Divinity doesn't say out loud "Hey, you. You have to pick ONe of these encounter abilities to use in an encounter". Also, Preserver's Rebuke doesn't scale with level.
Thunder of Judgement is badass.
None of the Dailies do it for me. However, the utilities are badass.
I notice that the Angel summoning doesn't actually have an AC or HP. It's more like a Flaming Sphere that can do OAs.
Something else that occurs to me. This class isn't as... well, it doesn't have any real "Wow" that the Druid and Wizard does. The druid has flexibility and finesse, the Wizard has cantrips and choice of dailies. This is rather vanilla, as class designs go.