In its current state, the lack of engine damage in the Multiplayer ruleset allows drivers to unrealistically decelerate their vehicle by exploiting the lack of engine damage.
For example, going from nearly the top speed and RPM of the vehicle to 2nd or 1st gear, slowing the vehicle much faster than normal (realistic) downshifting and braking.
Not only would this result in an almost certain loss of control in a real world situation, it would also probably result in a rapid disassembly of the engine.
Rivals is the most easily visible display of this lack of realism at work, with virtually all of the top replays involving this deceleration method. While less frequent and much more difficult to spot due to broken replays and no spectating, it is also commonly used in Featured Races.
This very arcade ability has no place in the official multiplayer playlists and should be removed by adding Engine damage to the ruleset.