Now that it’s been several months since the movie dropped, I think it’s safe to say that her power up is indeed “permanent”. Remember, just because she can turn it on and off doesn’t mean it’s temporary. Temporary would imply her alicorn magic running out and wait to gain more. She’s still an alicorn on the inside. The rainbow streaks on her hair prove that she still has that power. She can turn it on and off in any situation. While Hasbro currently has no plans to have her an alicorn 24/7 (meaning with actual physical wings and horn like Twilight) this is what they’re sticking with.
Ah, fuck, now everytime I see a G5 image or post Joker from XI instantly gets in my head… Well, more specifically, Joker from XIV which was remixed to fit Oswald’s personality, lol.
@Shimmering Spectacle
I think it’s Hasbro way of saying to us “see, for G5, this is our plan to make Sunny an alicorn later in the story. Is that clear enough for everybody? Now you can’t say we blindsided you, we’re putting our cards on the table here”