I feel that potency should grant a bit more to the rest of the squad, even for squadmembers without dots/debuffs.
My suggestion is that adding +5 % damage and +5 % healing power to the Potency-effect (beside the added chance to land a detrimental effect) for the duration of the buff would be adequate.
---
Could also boost the Tenacity-stat as well, giving not only resistance against debuffs but also adding +5 % def and +5 % incoming heal to the affected party.