
You're probably talking about the inward-drifting bikes. They are indeed broken, as combined with wheelies they are vastly overpowered. That means it takes a lot of skill with a kart to beat them, and I've met some people who definitely got into a competitive spirit due to that. Though trying to win with an inferior vehicle is a different story.
I'd say that the timed mini-turbo mechanic demands tighter racing lines than snaking. Since you need to drift for a specific amount of time for each turbo boost, if you mess that up, there's no second chance to get the boost. Since the boost can be done so quickly in Mario Kart DS, racing lines don't matter as much since if you mess one up, you still have plenty of time to do several more.