She’s on vacation maybe

@Whatthehell!?
 
Sorry, Rarara. You cannot force people to like what you like. Respect Indigo’s choices, and she’ll be a reliable friend if you are in trouble.

@Background is Best Pony
 
Ishi did say on his Twitter page that Indigo Zap was “on vacation somewhere”, so there’s your answer.
 
But in all seriousness, I agree with what Mayorlight said below about Kelly Sheridan only being able to voice work for one of the EQG specials and the creators simply decided to just save her for Starlight Glimmer in Mirror Magic. Of course, something they could’ve done was have Indigo be mostly silent throughout Dance Magic while using a few audio clips of her dialogue from Friendship Games for some quick lines. Does anyone think that might’ve worked?

That’s why she’s a tomboy

@Background is Best Pony  
Yeah, someone do it.

Can someone tweet Ishi or Kelly asking why Indigo wasn’t involved? I’m really curious, as is everyone else.

@Background Pony #1254  
In all seriousness, I do think Indigo’s absence did have to do with a decision by the production team to use Kelly Sheridan for Starlight Glimmer’s appearance in the upcoming “Mirror Magic” special.

@mayorlight  
Or Hasbro didn’t pay her enough when they did Friendship Games, so she decided not to be this one.

@mayorlight  
Or she was sick or out of town.

@mayorlight  
So now she’s a power ranger?

@09MurphyM  
My guess is Indigo probably either: (1) went to a Peace Conference, or (2) injured herself in a martial arts match.

@09MurphyM  

 
That didn’t stop RD from participating :p

@09MurphyM  
As an athlete, I feel like she’d be flexible/coordinated enough to make a good dancer as well.

Either that or she is more interested in athletic competitions rather than dance offs.

I can totally buy that