Overall good changes, all in the right direction. Making bigger shields better while keeping shield gating at low values was a smart decision. Open up lot of build possibilities on some frames.
Only thing that bothers me is having to sacrifice yet another mod slot on Catalyzing Shields. At least make it an exilus one, that would help a lot.
Also, what kind of enemies can one shot you at lower levels that a 1k+ shield needs 2.5 seconds of i-frames? seems wasted I think (it's only helping some frames that can generate shields like Mag and Hildryn-Pillage). It would have been better, maybe, bigger shields get bigger dmg reduction while adding armor into the equation.