[@Eisenhorn]

Yeah, I always imagined the teleportation was quite fast (assuming she wasn't going any super long distances, as I always imagined distance would affect how much she'd have to channel)

Most of the powers she's been casting, Vortex of Doom, or an overchanneled Smite, has basically been been her aiming at stationary, large targets or groups of enemies in team battles;[u][b] combined with her utter need to show off,[/b][/u] meaning she most likely overdid it in those cases ^^
If she was fighting a single individual in a fast duel, I doubt she'd try to cast a Vortex of Doom, and instead rely on faster powers, like a simple smite, barrier or short teleport.

I don't think they mentioned it anywhere, but I always assumed there existed a variable casting time, and that the casting time of an ability correlated to its power and effect.

Hence a Vortex of Doom could take up to dozens of seconds to cast or more, possibly minutes if you wanted to make it truly big, whereas a smite or teleport spell of low or average power might be almost instantaneous :D