I really like the intended philosophy of the changes, but I fear it's entirely missing the forest for the trees.
In my mind, right now, every damage type is one of two groups: It's either:
An incredibly good matchup for a healthtype.
Corrosive, Radiation, Impact, Puncture, Gas, and Cold go into this group. Their status effects won't do much in terms of damage, and that's not the point; In a critical build, this is going to help in making the kind of gun that can wreck an enemy without having to wait for status damage to finish them off. Radiation can bypass alloy armor and shred Indifferent Facade, Cold is a good catch-all against Grineer armor and Corpus shields.
or, has a strong status effect.
Slash, Toxin, Heat, Gas, Electricity. While these may not do much damage upfront, they have status effects that can become an incredibly strong consistent damage option. Slash bleeds absolutely ignore armor, Toxin and heat are easily added via mods and can counter shields/armor respectively, and Gas and Electricity works wonders in dense groups.
You may notice there are some damage types missing from this list, and it's all our current problem children.
Viral has an impressive +75% and +50% against the two flesh types, AND has the numerically strongest status type in the game; increasing damage vulnerability for health. Right there, why would you ever use anything else? It has the advantages of the two groups, and perfectly compliments anything you put it on and any damage type because it actually, literally INCREASES DAMAGE. This alone also means that the status effect negates it's own bad matchups, like against Infested and Indifferent Facade. Those -50% matchups are null and void when all you need is ten stacks of viral to completely overpower it. The efficacy of Viral is so incredibly good that it actively chokes build diversity across the whole game.
Magnetic is exactly like Viral except for shields instead. There are two things that prevent it from producing the same issue. The first is that Toxin completely trumps it. The name of the game is to reduce the enemy HP to zero - reducing shields to zero is just a step infront of that, and if you can skip it, you should. On top of that, once you get through a specific chunk of your enemy's EHP, the status effect and damage matchup doesn't matter at all. This will actually be somewhat addressed by the Corpus shield recharge scaling - keep it!
Blast is... actually useless. No seriously, in 99% of cases you shouldn't use it and you're handicapping yourself if you do. It's damage matchup is +75% against... machinery. Yay. I was excited for the Murmur, as the Culverin/Arcocanids use this healthtype. I experimented with having blast damage on my weapons, and even with a faction damage mod on them to help, it was just awful - Alloy armor is present on anything with machinery and it REDUCES BLAST. Halfway through I just gave up and went back to my corrosive tatsu. Not only this, but the status effect feels useless, and may even be mechanically negligible. Reducing enemy accuracy isn't effective or even noticable at all - how would I know the one Grineer or Corpus gunman missed some bullets among all of his other buddies that did? Even then, near the high end of accuracy scaling it seems barely effective. And that's even if your target uses a gun! Grineer butcher? Every infested unit? Murmur fragments? It's actually doing nothing. So if the damage bonus AND status effective is useless, why would you ever use Blast for anything?
What I'm trying to say is, while the unification of healthtypes is some great QOL, unless you address these issues, you're not going to effectively change the issues here. Something needs to be done about how oppressive Viral is.
While I'm at it: Don't simplify TOO MUCH. Modding for Grineer fodder vs. heavy gunners, or Murmur machines vs. constructs is pretty fun.