The second big difference (in Mario Kart Wii compared to the rest of the series) is the removal of snaking. Ever since the N64 game, practically every Mario Kart game has included the ability to get a speed boost by waggling the controls left and right as you powerslide. This has finally been scrapped, and now your speed boost is determined by how long you can hold the slide.
Some considered it a skill, I just considered it being an [Edited out by Infendo scrubbers]. Regardless, it’s been eliminated — that is until some hardcore nut finds a way to exploit the game in some new, more annoying way.