I've been known primarily as a Death Warrant user, and I would agree that the vehicle, along with Roadkill, don't necessarily classify as lightweight vehicles. However, they are the lightest vehicles that can be used practically in the competitive scene of Twisted Metal. This doesn't necessarily mean that a person can't potentially still perform well using Reaper, Crimson Fury, or Kamikaze, but it impossible to consistently perform well.

Speaking as someone who has used lightweight vehicles in five clan wars, the vehicle does not have the same offensive capabilities of any vehicle the has more HP than it, thus it is most useful to a team for the purpose of map control, between being able to navigate the map with efficiency, control valuable pickups such as health, and weapons like powers and stalkers. Furthermore must be efficient in the battlefield making full use out of these strong weapons to make up for the time you're not supporting the team. Typically it's not possible to make up for this purely in damage, which requires these players to take the fewest deaths on the team to keep their DD:Deaths ratio consistent, but due to unavoidable weapons, this typically isn't possible without the HP buffer a vehicle like Roadkill or Death Warrant offers.

It's pretty obvious that a year and half later, we aren't going to see any more balancing patches. To be honest, I doubt patches would have ever been able to fix many elements of the game, since the balance is off from the concept of the vehicles. No matter how much you buff Reaper, CF, or Kami, they're always vulnerable to unavoidable spam that even the most skillful players can't combat, which unfortunately deals too much damage. I was always against the Death Warrant HP buff, since I don't believe that increasing is the proper way to balance the vehicle (I never believed DW needed to be buffed anyways), and I feel the same about the lightweights. In fact, the best way to buff these vehicles would have been to reduce the amount of damage such spam deals, or removing such weapons in the first place. I personally attempt not to auto-lock remote bombs on anyone, and if it occurs, I never cook them anymore since I don't appreciate that tactic.

Completely agree with what Muddy stated, very well put.  The only real advantage of the faster cars is in taking away most of the good weapons and healths from the other team.  DW equipped with lots of power missiles/mega guns/stalkers can be quite powerful. But the biggest factor is that you are taking away hard hitting weapons from the other team.

Hellbent's point about picking the appropriate car for each level supports this theory.  In California for example, DW is pretty decent because there are probably almost 10 power missile pickups.