Agreeeed~ If these are legit, and aren't going to cost a small fortune to purchase, I will definitely be getting some once they arrive. All of the toys they've released thus far are far more reminiscent of previous iterations of the series, and I just don't care for them. But if they actually start making some show-accurate G4 figures, I'd be all over that. :3
On the topic of Wizard of Oz, I just can't see Applejack being Dorothy, if I'm honest. Besides being a "farm girl", she's nothing at all like Dorothy; and even on that note, Dorothy wasn't really a "farm girl" so much as an "I-Live-On-A-Farm girl". Could you imagine her character doing a single day's worth of real farm labor? Not a chance.
My vote would be on Twilight as Dorothy, and Celestia is practically perfect for the part of Glinda. Both being the wise, benevolent rulers of the land, they're essentially the same character in their respective worlds.
Aside from that, I like all of Radio's suggestions. And I think Fluttershy would make a better Lion than Big Mac or Gilda. Mac isn't really cowardly; he's just not a big talker. And Gilda, while a great contender for a re-imagining of the story, is just too hot-headed for a direct conversion of the original story.