I agree with others. PVP wouldn't notice an EPTS change because it would effect everyone equaly. But in PVE content you out and out require that resistance boost on non-escorts to sucsesfuly tank incoming damage via sheild tanking. The game is innatelly balanced around this value in PVE. Nerfing it would be hugely detrimental IMHO.
As far as other EPtX abilities go:
I'd say the EPtW damage buff just needs to be extended to the same duration.
EPtE could do wit the flight speed buff swapping for a+20/40/60 defence boost and a +X% turn rate boost, (the flight speed buff is onyl worh it on an escort right now as nothing else turns hard enough to be usable at that speed).
EPtA is a LOT more arkward, and i'm not sure what to do with it eithier.
Oooook... so let me try this again. I am an Engi fed that primarily runs cruisers. And I can tell you this from quite a bit of experience in PvE. EPtS is NOT overpowered. It's usefulness in almost every situation might lead those to think that, but it's not. Far from it. It might be overuseful, but not overpowered.
Let me just say this. Try to tank a tac cube/gateway without it. I wish you luck and will send flowers to your funeral. Try to take on Spheres and Nanite Spheres with their tetryon beams that proc every 3 hits without it. Again, I will send flowers to your funeral. Now do the exact same thing only this time use EPtS along with whatever you were doing before. I will pay for the strippers at your celebration.
Please. Not overpowered. Just right. And yeah, the other EPtX are a tad underpowered in comparison, but they are still useful.