I understand, you want procs to be competitive in PvE, while also not broken in PvP.
When procs didn't scale, PvP players broke the balance using procs on chars without damage stats to achieve strong damage burst combos.
Now procs scale, but that also means players will stack up the stat needed for scaling and use all-procs setups to do insane burst. Or insane healing, for premade groups. But people already did a lot of threads about it, I don't want to repeat.
What went overlooked here is proc conditions.
PvE doesn't care about proc rate, as long as they can keep a decent uptime, because PvE cares about DPS, not about burst.
PvP, on the other hand, do care about reliability. I remember that previously almost all procs had low percentage chances. At some point, we got a lot of 100% chances on procs. While this surely do increase DPS a bit, it increases burst A LOT.
When you need to just click one skill (or even do auto) to guarantee a trigger, it means you have guaranteed burst with timing you can control. Even if that is DoT sets, it still counts as burst, because DoT skills require GCDs to apply, unlike dot set procs. GCDs matter in PvP.
If you want to tone down procs in PvP, think about how to make proc conditions harder.
Bit of advice: nobody likes random. Don't fall back on random. Take example of Explosive Rebuke. Or Azureblight.
Make it so you need to work towards proc condition, not just slap an opponent with Stampede to apply 3 procs in a single GCD.