this is all based on info you can find in the tanking stat weights thread, along with the damage reduction info from AMR of full 63 jugg tanks.
I would really recommend you check your math again. The only thing, from a mitigation standpoint, that Full defense has over the hybrid is 4% shield chance. Considering that stat allocation provides to all of 50% absorb value at best, this means all of 2% reduction in M/R damage. hybrid's advantages are 25% more Blade Storm (9 sec CD compared to 12 sec) and 4% K/E DR: since M/R attacks can only ever be K/E damage (there are no I/E M/R attacks in game), you're getting roughly twice the mitigation gains against M/R attacks (it's not explicitly double because DR and shield mitigation are calculated at separate points; the DR is actually going to contribute *more* because it applies against the ~67% of the attack that aren't parried rather than 33% that are shielded) as you would be getting the bonus to shield chance. And that's completely ignoring the higher contributions from Blade Storm.
I would *really* like to see the formulas you're using to draw your conclusion since, in all honestly, everything you're saying *flies* in the face of pretty basic math.