Really, it's just me

wings: “humans don’t like things they can’t understand, so if we’re going to levitate we should have wings. in fact we should probably have lots of wings, since we’re so big and impressive. humans like wings”

loud, booming voices: “fuck off Azrael the humans needs to be able to hear us.”

glowing: “no no no, it’s about visibility, right? the main human sensory organ works by detecting light, so if we emit light…” 

wheels: “why the hell are you shaped like that?” “piss off, the humans are really proud of this invention”

multiple faces/eyes: “it makes me relatable” “i swear to God it doesn’t–” “i need to see in every direction” “ Azrael you are a supernatural messenger of god you do not need–” “THE HUMANS NEED TO KNOW I’M WATCHING”

multiple limbs: “humans have lots of limbs! they like limbs” “look i let you keep the wings but–” “how do you expect me to walk?” “70,000 feet is not a reasonable number of feet, Azrael!” “fuck off i’m ENORMOUS” 

Old Testament Angels look like that because life in the ocean outnumbered life on land, so naturally when they visited earth they modeled their appearance on the most common lifeforms. Hench you get things like

radial symmetry (i.e. angels shaped like spheres) which is objectively cooler than bilateral symmetry (starfish understand this)

Very Numerous Limbs (2 is not the average number of arms in the ocean)

random glowing (bioluminescence)

just generally being objects of Absolute Terror to land dwellers

a thousand eyeballs being the Norm (have you seen scallops)