Wicked is a far better prequel in all respects, but that doesn't mean that the timing isn't unfortunate for a film version.
Yes, there are obvious similarities in the subject, but also the specifics of it:
Witches are all younger, prettier, playing into an unrequited love scenario that drives a lot of their motivations.
The best thing a film version of Wicked can do is stay the hell away from the 1939 MGM film in all ways, other than the ones already written into its story, which are subtle by comparison to this current (mediocre) film homage---particularly with the visual look (art direction, costumes, and makeup).
I think if it's approached in a completely different way, people will be open to (what they will probably perceive anyway as) a "reboot" of the Oz prequel idea.
"Jaws is the Citizen Kane of movies."
blocked: logan2, Diamonds3, Hamilton22