I'm afraid the talents Parry and Reflect, by RAW, could lead to a power creep since they all stack... so you could have 21 Parry or 11 Reflect (for the right price) for only 3 strain each. I think the strain cost should increase with the potential soak gained, much like dodge or sidestep or defensive stance need to spend 1 strain per rank to upgrade opposing difficulty check.
Did you catch that Knight level droid who can tank lightsabers with his face? (the build posted was 11 soak, but simply giving it Superior laminate armor brings it to 12 while staying well within knight level funding, and there's another Enduring in gunner, plus the entire marauder tree, and a dedication for 6 brawn, for far less points than grabbing all the parry and Reflect talents. (and no strain at all)
He could practically tank a vehical blaster cannon.