Clearly I must be living on another planet, because I can only think of 2 frames I'd ever bother using vitality over redirection (and you know exactly which two I'm talking about). On practically every other frame shields are flat out superior to health because most frames have next to no armor for damage reduction. Also: shields recharge, health doesn't. The only time health ever becomes superior to shields is when you have high armor, and if you have high armor you are going to be using at least 2 defensive mods. I consider that a waste, why waste 2 slots when I can get by with one? Shields are perfectly fine where they are at, if anything they are more than fine where they are at since they were just fine before they added all of these augments and overshields and team restores.

Granted magnetic and toxic are kind of bullshit against shields, but that has to do more with the damage types than anything as viral and corrosive are equally bullshit against health (although you'll certainly see less enemies using those. Instead of overbuffing shields, why not fix the magnetic proc from sapping ALL of your shield AND ALL of your energy and make it either one or the other or half of each. Also, toxic going through shields makes almost no since since if that logic flies then several other elements should be going through shields too. These elements are the problem, not the shields themselves which 90% of the time are straight up better than health. I don't think turning shields into basically recharging health with armor would do anything to combat either of the problems you listed.

I mean, you pretty much said it yourself that toxic and magnetic are the problem and then you suggested a solution that does literally nothing to combat either of those problems. Doesn't really make sense to me. Fix the source of the problem, not apply band-aids that do nothing to address it and create their own set of problems.