So, I can easily envision that Johns thought something like, "okay, Alan, you don't want us using 'your' concepts for DC-owned characters? Got it. So we'll just take probably your most original version of one of them and just retcon it away to before you wrote it. Happy now?"
Nah, you're assuming Johns is a spiteful little bitch, but I don't get that vibe from the guy at all. Let us remember that because a guy can't write doesn't mean he's the embodiment of all evil in the universe (Loeb's mass genocide in Africa notwithstanding).
They've been talking about "taking back" some Vertigo properties for a few years now, and I'm guessing this is simply a high profile way of doing that. I see no problem with that: no one was doing anything with Swamp Thing in Vertigo, anyway.
