Cutie Mark Crusaders, Ponyville Flag Carriers.
This new Mane Character doesn't really seem overly powerful... on initial inspection, it seems somewhat weak and slow to flip.
However, I think it's potential is in its deck of Foals.
Although there are many foals characters, it is in Twist, Such a Treat, that we see this potential come to life!
This Friend will nearly always be at +1 (power of 2).
Played in conjunction with (preferably up to 3) Pie Family Rock Farm, Twist, Such a Treat, will power up to +4 each turn (on the drawing of 4 cards every turn), making her 5-power. (Have up to 3 in play and it could prove disastrous to your opponent!)
Now, couple these cards synergistic potential with Diamond Tiara (troublemaker) blocking your opponent from scoring on either or both problems and you're free to score every turn.
Diamond Tiara also powers up based on the number of Foals at her problem. Only counting Twist, Such a Treat and Cutie Mark Crusaders, Ponyville Flag Carriers, that in itself is +4. (Making Diamond Tiara at 8-powered Troublemaker!)
Throw into the mix a deck built upon Foal Friends and this could prove devastating.