As a side note, today in the car on the way to work, my husband and I had a long discussion about how, of all the character in Good Omens, he relates best to R. P. Tyler.
In a Facebook Neil Gaiman fan group I'm in, a member posted a screenshot of a thing from Twitter. It basically went: Aziraphale catches someone trying to steal a book from his shop. He grabs the book away, coshes the man in the back of the head with a baseball bat, and shouts, "Begone, thot!" (Look it up. I had to.) He then turns to Crowley and asks, "Was that right?" and Crowley, who's filming this with his phone while cracking up, tells him, "You did fine, sweetie."
The responses to this in our group was, "Adorable!" and "How cute!" and "That's what I love about those two!" Meanwhile, I'm thinking, "Did I watch a completely different show / read a different book from these people?" Aziraphale physically assaulting anyone, and even knowing a word like "thot"? The Aziraphale I remember was idealistic and nostalgic, but not a fool. Crowley laughing at Aziraphale and allowing him to continue with his misconceptions? The Crowley I remember was interesting because despite his demonic nature, he always tried to take care of Aziraphale, though often in a gruff, sarcastic way.
That's what I don't get, how you can take characters you love, change them so much that they're almost unrecognizable, and still consider them the same characters just because you kept the names. Sometimes I feel that people often don't really grok the characters; they instead love the idea of they form in their own minds about them, their headcanon. I do that sometimes, but I try really hard to correct it. (Example: I have a headcanon about the end of "Journey's End" that I really embrace, but as I write my current story, which is about that episode, I'm working hard to keep that headcanon out of it.) I totally understand the need to change the characters when working in an AU, but when you're staying canon (or at least implying that you are), well, I just don't get it.