the major idea behind power sliding remains the same. you're drifting around turns to maintain speed and keep a tight turn. all they took out was the annoying and somewhat excessive part where you had to rapidly move the joystick back and forth to get the speed boost.

I think they basically streamlined power sliding without changing the nature of the technique. I've only had MK Wii for one day, but it seems like they stayed true to the nature and techniques of mario karts' past.

doing tricks in the air for speed boosts is an excellent addition.