SS4 brings a fighter to their natural limits. Whilst Raditz has nowhere near the potential of Galu or Vegeta, to say he lacks so little he could never surpass 2nd form Freeza seems absurd. SS4 Raditz oneshots.
Fair enough on your assessment of SSJ4's power. I use the x500 factor, give or take depending on said potential. I know it's not generally accepted but I prefer numbers over anything vague even if it's flawed or doesn't hold up on a debate stage. It's nice and easy for headcanon. Just pointing out muh motivation for the battle.