I like Crash Mode, although generally speaking I think Burnout 2 had a better implementation.
In Burnout 3, it mostly boils down to grabbing the 4x token and managing to hit a few vehicles in the process. There were a few crash junctions where getting the 4x wasn't always a guarantee of success, but for 80% to 90% of them, that's how it played out.
Burnout 2, on the other hand, didn't have multiplier tokens, and your multiplier was determined by how many cars you crashed. This formula isn't entirely flawless either, but overall it was more rewarding.
Crash Mode in Burnout Revenge is supposed to be set up somewhat like the one in Burnout 3 in that it has Crashbreakers, but they are removing the multiplier tokens.