I have been looking at the T3 armor options, if my information is correct the following armors have the best protection:
- Energy: Energy Vest: HWT Range (18.32)
- Impact: Devil Skin (17.11)
- Piering: Brig Warden's Stab Suit and Aurorahunter both (12.00)
At the same time the T3 weapon with the highest damage is doing piercing damage.
So i think players could us a T3 armor with better piercing protection.
Bit two edged actually if campaign opponents also get to use it :p
P.S. The best T2 armor vs piercing actually is better and the best T3 armor vs piercing: Freebooter Rave Suit (12.51)