Long story short, someone with a “god complex” is a big poser. If Whale was an actual god, there would be no complex, he would not have to refuse to admit the possibility of failure because there is no possibility of failure when you are a god. The fact that Archie diagnose Whale with said “god complex” makes him desperately human.
Ah, yes, but at the time this diagnosis was supposedly made, wouldn’t he have in fact been “desperately human…” Remember that there were no actual gods in Storybrooke (or princes, or dwarves, or fairies…)