Everything you just showed is exactly why no sane game developer would use DT as it was in Fo1/2, and why DT in New Vegas had a bleedthrough on it.
At no point in a game should you ever become immune to damage from any source because it trivializes the game's content.
Game balance is always more important then hardcore realism. Every, single, time.
Not even games that even try to have some basis in realism work like that, bot that exact reason.
Are you literally that fucking dense?
No, DT does not trivialise a game's content, DR DOES!
What is the point of DR, if even the mightiest power armour can be matched by some leather garbs and some chems/perks?
In FO3, I managed to get the cap of DR with some pretty shit gear, making power armour useless.
In FONV/1/2 (Modded for no bleedthrough), more DT is ALWAYS a good thing, and there will always be a big bad enemy to deal damage to you.
Even with the monstrous DT AND DR system which 1/2 had, enemies could damage you.
To make this clear, even with 90% DR, and 20+DT, enemies could still hurt you, by no means say it makes you invincible.
Just a few hours ago, I was torn apart by mere GECKOS, who managed to get some crippling critical hits which did insane amounts of damage, despite myself being in Enclave power armour.
In a purely DR system, armour isn't armour, its just making your healthbar bigger, why not simplify it more by simply giving armour a +health bonus instead? Its the same damned thing.
DT is armour, DR is just a bigger healthbar.
I honestly cannot comprehend how you think such lazy armour systems, which nearly every game uses, is the best thing.
No, being a drone who follows 'whatever everyone uses' is not a good thing, at all.
The best systems in games are thresholds, and they always will be.
Fallout used it, War Thunder tanks use it (On a more complex scale), and countless other games use a threshold system instead of a 'percentage resistance' system.
Balance is one thing, and 'hardcore realism' is another.
But don't you dare say that a raider with a .22 revolver should damage you in any way, barring a turnbased critical hit.