Well the chances of them ever making it to a Smash game are next to 0, but if it somehow happens, I agree this would be the best way. They would only add one character, so this way we can have 2 for the price of 1.
 
B: Magic Beam (Can be charged)  
B-Forward: Gallops nervously while reading a tome, which serves as a battering ram.  
B-Up: Teleport. To any direction.  
B-Down: Spike Shield (Levitates Spike in front of her to bounce off missiles)  
Grabs: Are obviously done with telekinesis.  
Taunt 1: Plops down on the ground and begins reading a book.  
Taunt 2: Has Spike send a letter to princess Celestia.  
Taunt 3: Takes out her “to do” list and begins making checks.  
Final Smash: Either calling the rest of the Mane6 to use the elements (or Rainbow Power) or maybe using the Age spell on Spike, making him grow gigantic to shoot a giant fireblast. This one would be more original imo.

Nice try OP.

I think this is a fake.

Oh boy.

@Background Pony #EB47  
Still, is not from Sakurai himself.

@Background Pony #EB47  
That’s great.

@FanOfMostEverything  
Taken from the 8chan thread on this:
 
“I would have Twilight Sparkle and Spike fight together similar to Duck Hunt, Ice Climber, or Rosetta & Chiko. But, in Super Smash Bros., Twilight Sparkle and Spike will probably not be selectable soon.”

goddammit, look at my grammar

Wiat, this is from sora? no from sakurai himself? also no source, surspicious.

iAdgnsjfnfsidm-
 
What?

Translation?

SAKURAIIIIIIIIIIIIIIIIII!