Its not about potency, its about gameplay. You now don't have to track Noxious Gnash, which removes a noticeable part of what made the Viper Rotation interesting. Instead of using both Dreadwinder Cooldown and Noxious Gnash timing as a measurement of when to use Dread Fangs over Steel Fangs, you now just alternate the two.
Potency can be adjusted up and down without many issues, this is not where peoples criticism lies.