@Frustration in Excelsis  
To be fair, some fans predicted Twilight was going to get them too prior, I recall. There was even some fanfics, and fanart of her like that, as well. So it wasn’t just Spike.

@Beau Skunky  
I think the thing about Spike getting wings is that a not insignificant portion of the fandom already expected it or wanted it by the time the episode came along.
 
If you will forgive me a bit of rambling: fandom consensus on whether or not Spike would get wings, I think, changed a fair deal as the show progressed. In Season 1, when we had only seen a grand total of three dragons on-screen and Spike shared little enough either physically or physiologically with the other two, there was certainly plenty of room to speculate that Spike perhaps belonged to some species of wingless dragon. This, I think, may also have been tied to an early fandom trend for speculating that the way the ponies were divided between earth, air and magic variants might have been reflected among other species. In this sense, Spike’s winglessness might even have supported this speculation – whereas “Basil” and “Reginald” might have been “air dragons”, Spike might have been the dragon equivalent of a unicorn or an earth pony.
 
Then “Dragon Quest” came along, and did three very significant things: it showed a very, very large number of dragons, every single one of them winged; it clearly showed Spike as identifying as one of this dragons, and the other dragons not contesting this belief; and it did not show any dragons calling attention to his winglessness, or at least only doing so in the contest of his youth. Garble and his gang only ever called Spike a “runt” and a “baby”. Garble even made a comment about Spike flying in on his mother’s back, implying that he considered Spike to likely be the child of winged dragons himself.
 
This was magnified a while later by “Gauntlet of Fire”, where, despite the honestly ridiculous levels of physical variation between all the dragons seen, everyone but Spike was winged. As more and more winged dragons showed up on screen and more and more of the dragon species’ culture and biology was talked about, I imagine that finding a space to put a species of theoretical “earth dragons” became more and more difficult. Likewise, no indication of an internal tribal split to match the ponies’ appeared in any species seen on-screen. As the primary thing consistently separating Spike from the other dragons where his size and age – that is, he was a baby and they weren’t – I imagine that it became more and more common to latch onto that, rather than Spike belonging to a naturally wingless strain of dragons, to explain the difference.
 
I think that fanart and fanfic are a good way to observe this. Art and stories featuring Spike with wings, and specifically as gaining them as he grows, become more and more common as the show went on. By the time Season 8 rolled along, I feel that the idea of Spike gaining wings as he grows had become a very widespread assumption in the fandom.
 
Hence why I think that Spike’s wings were so well-accepted. By and large, the fandom’s reaction to that episode seems to have been more along the lines of “well, finally!” than anything else. It didn’t even herald any particular change in how he’s depicted in art and fanfic.

@Frustration in Excelsis  
That being said, I don’t mind him having wings, but I still find it funny that more people accept that, then say Twilight getting them. It’s one of the few series changes that yielded very little drama compared to say Flurry Heart’s birth, the Friendship school, certain villains being reformed, and such. Normally, bronies hate change as much as Sonic fans, yet Spike getting wings was pretty well-accepted regardless.

Man, reading through old comments with the benefit of hindsight is always an experience.

Looking good, Spike mah man.

@LadyTheRainicorn  
Not all ponies have wings, I don’t see why fans assume every dragon needs them. Being wingless makes him more unique to me.

@Karackas  
Like “prom” I guess.

His “prance date?”

@DragonWraith  
Probably nearer to the end of the series.

@dt  
@Background Pony #A492  
@Itsthinking  
Yeah, it’s only been, what? Two years, in-universe? It could definitely still happen.

@Background Pony #A492  
Could still happen.

Could have happened. Should have happened. Didn’t.

@dt  
I know, but its fun to pretend D:

It’s funny because it won’t ever happen.

I wouldn’t mind seeing Spike get wings

Really cute designs.

I love these designs, especially the “awkward teenage Spike” :3