Persistence relics are an interesting thought and this 4p will likely just amplify it as an already strong trait. Remember that partial ticks of rejuv should still proc the 4p, so this may essentially reintroduce haste break points in that you want to push for that extra bit of haste if it can push you from 80% partial tick into 1 full tick and a 10% partial tick, giving you an extra 2% chance proc.
Also will the 4p proc on overhealing? After being unsubbed for sometime I am unsure of how blizz usually words things like this, I assume it will only proc on actual healing.