Discussion - Is Sunset Shimmer an Alicorn? · 5:54pm Apr 9th, 2016
While I of course worship Best Human and think she has no need for those silly wings to prove her greatness, it can't hurt to speculate if she's got them or not.
The biggest evidence of Shimmercorn is of course, the wings. At the end of Friendship Games she becomes Sunset Phoenix (I dislike "Daydream Shimmer," this is my term for her), there's My Past Is Not Today, and in the novelization of Rainbow Rocks she apparently grows wings when she ponies up.
Now, a point on the transformations of the humans - it's very inconsistent and I have no idea why. I'm talking about the horns. I really don't know why Rarity and Twilight don't get horns when they pony up. They do in the novels but not the movies. Related to that point, I don't know why Midnight Sparkle and Sunset Phoenix got their horns when they ponied up, no matter what the fics on my alt account say. 
Point is, it's a bit fuzzy on how the transformations work.
That aside, though, the wing argument isn't very strong. The major reason is that the wings Sunset grows are different from the ones Twilight, Rainbow Dash and Fluttershy get, and even from the ones Midnight Sparkle got. Those four got pegasi wings, feathered and structured. Sunset's wings, in both Friendship Games and My Past Is Not Today, has flaming wings. They more likely symbolize her magical powers and her phoenix motif than her being an alicorn. I don't know what type of wings she has in the novelizations, but the movies take precedence here.
The wings aside, if Sunset is an alicorn, how did she earn it? The show explicitly states becoming an alicorn is usually rewarded on normal ponies for achieving some great magical task. And Sunset hasn't. True, she united her power with the Humane Six to make the Rainbow Alicorn (more on that in a moment), and was able to take on their power to become Sunset Phoenix. But in the latter circumstance she was using the magic capture device to help her, and in the former she didn't do much directly. Against the likes of Starlight Glimmer (don't get any ideas, showrunners), King Sombra, Star Swirl the Bearded, Sunburst, and Shining Armor, has Sunset really done anything that impressive in terms of magical ability? If you don't restrict it to unicorns and their magic, I'd even argue that Rainbow Dash's mastery of pegasi magic to use the Sonic Rainboom is pretty impressive.
That said, it is implied there's a second requirement to become an alicorn - a higher destiny. Cadance and Twilight were both marked for something greater, bearing the Crystal Heart of the Mark of Magic as their cutie marks. So, while other ponies have done more magically impressive things than Sunset, perhaps they just don't have a higher destiny waiting for them and she does. So, is there evidence that Sunset has a special destiny?
Well, she has certainly taken up an important role safeguarding the other world from magical beings and being a keeper of the portal. Her ability to combine her power with the Rainbooms is particularly impressive. Speculation abounds about a seventh Element of Harmony forever, but this is the closest we've come to it actually being canonized. Even if Sunset doesn't bear some secret seventh Element, she still combined her power with the other six. Call it the Elements, call it Rainbow Power, either way it's something we haven't seen any pony do before or since. Additionally, in the comics, Sunset looked into the mirror to the other world and saw a vision of herself as an alicorn. Why this happened is unknown since it's inconsistent with what we know of the mirror, but again, comics.
Two things that should be not taken as evidence of a special destiny is her cutie mark, and that she's Celestia's student. Cutie marks themed after celestial bodies are very common - Sunburst, Starlight Glimmer, Trixie, Moondancer, and Twilight Velvet and Night Light, all show that sun, moon, and star-themed cutie marks and names are just a bit of a trend with unicorns. As for being Celestia's student, that actually isn't so special. All that we see from the show and expanded universe materials like the comics imply that Sunset just went to the School for Gifted Unicorns the same as many other ponies, and Celestia just happened to take a personal interest in her. She did the same for Twilight, yes, but there's little to directly state that Celestia recognized a special destiny in Sunset. She recognizes Sunburst by name, so either Celestia remembering her school's student is just something she does because she's nice, or it's further proof that Celestia's interest in a pony doesn't mean they have a special destiny.
Finally, and more damning - this is all speculation. Until Sunset one day returns to Equestria and finds herself looking at a shiny pair of wings, it's impossible to say with certainty if Sunset has become an alicorn. However, the evidence implies probably not - she doesn't have the right type of wings, she hasn't done something appropriately impressive to earn the status, and she may have a special destiny but possibly not.
I err on the side of wings for Sunset. We've never seen her transform since the climax of Friendship Games, and it's not like Twilight didn't get some assistance from the Elements, what with the massive harmony lasers that may have reduced her unicorn body to a black smear on the library's floor.
It is ultimately uncertain, but all of the prerequisites seem to be in place.
I really don't understand why this is a topic for heated discussion, yet this is the second time in two days I've seen it mentioned. <.< They were just magical fire wings, they don't mean shit.
3859139 I just like excuses to talk about Best Human.
To paraphrase Fluttershy, I don't think she's there yet. She's still got a lot to learn and a long way to go before she--assuming she ever returns to Equestria--earns her ascension.
Plus, y'know, she has to actually be in Equestria.
3859150
Well, I can't fault that :O
One other piece of evidence you may not have considered: Her outfit. When she transforms into a phoenixcorn or whatever you want to call it, her normal clothes turn into some weird outfit that looks like a cross between a royal dress and the toga of a greek goddess. To me it looks like a princess dress, so I would count it as evidence on the side of alicornification.