The only way that no CP PvP will be able to persist in this game without serious nerfs to the damage potential of proc sets it to LIMIT the number of proc sets a player can slot to 1 just like with mythics, the fact you can wear malacath and 2 burst procs resulting in actual one shotting is severely unhealthy for balance in this game.
Free damage procs defined as damage which costs no resources and has varying degrees of avoidable mechanics (hunters venom needs to have mitigating factors or lose it's damage or aoe function), stat or WD/SD procs should be seen as separate from free damage procs, they have short duration and mitigating factors because they are tied into the skills a player uses which are far better balances than proc damage who's only function aside from ruining the PvP experience is to help new players get through vet dungeons without knowing how to dps, please find a way to keep them from destroying battle grounds for everyone else.
I see no reason at all why they could not be limited to one, I don't like the idea of restricting peoples creativity for builds but having parameters to work with to make something balanced is a lot more fun than just slap on 2 of the sets which were never properly tested or accounted for in no CP and profit from it.