Path of Ruin is undertuned. ATM picking it is a dps loss. Within 45 seconds you can 3xPoR for 9 hp cost or 1 WoA + 4 DS for a total of 9hp cost. And the latter does way more damage.
I don't think removing the cooldown would work since it would simply replace DS ,and possible TV too, which isn't that interesting. Removing the hp cost however could work.