The command imo should stay as it provides coverage for when mass RDMers come through town - but if the argument is about how overused it is by staff for players etc, then thats a different story.
As it stands, like Cal said, it should be the case of if you want a Comp, the person who killed you, friend or not, will HAVE to get punished. Now whether or not this happens as it should, again different story.
But making some guns uncompable would make it very risky, but given how often VDMing and RDMing happens, i feel it would give more of a headache to the masses in the long run.
If it comes to also negating the immediate escalation to weaponry - then like pendred suggested else where having delays in pulling guns out should make it better. Someone else suggested (i think cookies) the usage of automated /mes which would go in hard and be a great foundation for RP improvement too.
All in all, keeping the command is definitely fundamental but how its used and what goes on around/before the usage of that command is even more important and should be addressed for the "overuse" of comps is just a symptom imo.