Well, let's have some context here.
Rainbow Dash can fly fast enough to break the sound barrier - she has been stated to be one of the only pegasi in
history to do this, and she did it as a
child.
Fluttershy can stare down a
dragon
Rarity can cast illusions large enough to fill an entire room, not to mention individually and precisely manipulating who knows
how many objects, and blend fabric together (which cannot be easy at all).
Even setting aside Pinkie's cartoon powers, which don't count for being rule of funny, she's still got her Pinkie sense, which is enough to overcome or at least predict most dangers, making her largely untouchable while active.
Applejack can harvest at least half her orchard on her own, along with other tasks at the same time - an orchard which spans several
miles at least, and is skilled enough to come in at least fourth place at every major rodeo event, which are fairly wide-ranging.
Big Macintosh can pull a
house with no visible effort.
In context, Twilight really isn't that overpowered. Everypony else is obscenely talented in one way or another, hers is just the flashiest.