You know, I think I prefer Mecha Alicorn Sunny over Power-Up Alicorn Sunny.

@GaruuSpike  
I agree. And they’re gonna need it.

While I think that Sunny’s alicorn form is probably just a temporary “power-up” — due to the non-corporeal appearance of her horn and wings, as well as the rainbow stripe in her hair evoking the “Rainbow Power” transformations of the Mane 6 — I would not have blinked an eye, if that was a true ascension.
 
Remember that Twilight started way behind in the friendship game, only starting to learn about it as a young adult, whereas Sunny was raised with the values and lessons of friendship from foalhood, and has been working to spread its message her entire life. Surely, succeeding in re-uniting the three tribes and rekindling the Magic of Friendship is no less a feat than completing an ancient spell?

@Ebalosus  
They wouldn’t say ancestors in the movie, that’d be too much assumption on how the TV show would go. But with Argyle’s starburst mark, it’s a fairly strong familial connection.
 
The mane 5 could be more of a “spiritual” reincarnation of the Elements. Since that’s what the mane 6 were. “Spirits” that represented the Elements.
 
Or Argyle is a writer, and G4 Equestria is all part of Sunny’s imagination based on the stories he tells.
 
It’s all speculation and head-canon this early, but still fun to think about.
 
Edit: realized too late “a” ment alicorn. Be one more thing for them to discover and learn about, with Twilight as an example. I’m sure Sunny would have a lot of questions on why she disappeared and why only a handful of alicorns ever existed.

@moonlightaveger
 
I didn’t think so.

@Ebalosus  
I did that for you. They don’t use the A word.

Did they even say the “a” word in the movie? I’ll have to keep an ear out tonight when I rewatch it.
 
@sxcbeast
 
Dear god I hope not, as that would be playing it a little too close to g4.

A lot of theories out there about the Mane 5 being decendants of the mane 6. My bets on Sunny and her dad being from Twilight. Argyle mark has the same Starburst as her.

The fourth one could be Twilight shining her light upon Sunny to bless her. Twilight’s Cutie Mark just feels so sacred here. :3

Sunny’s trying to solicit acceptance of the other pony tribes, and this saves time.
 
Becoming an alicorn is only a problem if Sunny has unlimited power AND unlimited authority, and I don’t think G5’s individually-governed city states will allow for the latter.
 
And a relatively-weak character that makes the best use of their meager tools to solve a problem is always more appealing than an overpowered character that can solve every problem with a sledgehammer approach, like G4’s alicorns (especially Twilight).
 
Good luck, writers!

I just love that in the end she kinda was, but wasn’t. I’m disappointed. If there was one thing I liked about alicorns was that they became so on their merit and whatever magic that did it just didn’t care. She should jus have straight became an alicorn. Period.

@Enmity1498  
You haven’t seen the movie yet have you?

I think most people know that Sunny will become an Alicorn in the future, especially since the three gems (or elements) heavily implied it the most out of all three of these references! Honestly, I personally think it will take a while for that to happen, since it also took a while for Twilight to become an Alicorn in G4. However, I think that it is all but confirmed at this point, and we are just waiting for Sunny to develop a bit more before that kind of transformation takes place.