The bombs are a lot bigger than Hiroshima.
I am aware of what the wiki says.
But we're talking about the actual bombs actually shown on-screen here, not waffle from the wiki from the inconsistent info in the games. None of the ones shown even remotely approach 200 KT, no matter how much you tweak the variables. Let alone higher figures.
Re-watching the scene, I did notice one potentially important thing - these are
ground bursts not air bursts. They were not hit by warheads from ICBMs, SSBMs, or even a cruise missile. They weren't bombs dropped from a plane (which also normally airburst - Hiroshima and Nagasaki did for example). They were detonated at or beneath ground level (which includes up to a few stories up).
So that means they could be larger than my initial estimate. When a bomb ground bursts, the radius of all aspects of destruction except the fireball and radiation zone are like 20-30% smaller (very crude generalization).
There's a grim tool you can play with here to see historical nukes:
NUKEMAP by Alex Wellerstein
NB the destruction radii are quite conservative, rather than maximalist.
Even 150 KT ground burst would have caused 3rd degree burns at 4.7km - no-one would be walking or riding away, they'd be rolling around and screaming. Even a 20 KT bomb does that out to nearly 2km on a ground burst, and would have caused a ton more flash-fire than we saw.
So I would suggest the bombs we saw were probably more like 10 KT, given no-one caught fire, was blinded, or got any burns, and the cars didn't even have their windows shattered, only the huge ultra-vulnerable windows of the house did (meaning you're beyond even the "light damage" radius, where basically all windows will shatter).
They also had the sound/blast travel unrealistically slowly, but I'd put that down to artistic licence.
But them being ground bursts is very interesting (and definitely intentional given the complexity of the FX). It suggests that perhaps the Vault-tec alliance's plan to start the war themselves was very, very literal, and they just drove bombs into position. So perhaps you could say the wiki is correct in that the FO military typically used 200 KT or more bombs, but Vault-tec used significantly smaller ones (perhaps to ensure the right people could be in the right places to get to the shelters).
The other thing that's a little interesting is Janey is with Cooper,
but her mother surely knew when the bombs were being detonated, so I wonder what is going on there.
Also even a 10 KT bomb in the middle of a bright day at 4km would almost certainly have blinded anyone looking in the direction of the bomb, as Janey was, but perhaps the blast was slightly underground? The trouble is the flash is from the fireball, which would have been nearly 450m wide. So maybe we just have to say that was unrealistic - or it may be that the bomb was significantly underground -
the one used on Shady Sands almost certainly was underground, from the massive crater but limited blast damage.
I didnt find any issue with Fallout or most programming in general. However, Nolan and Villenuve do some crazy mix as you say. Im not sure if the purpose is for theatrical experience that doesn't translate well or what. Those seem to be the only places I get a slight issue keeping up.
It's the mixing, and also Nolan (not Jonathan Nolan, his brother, the film guy) is intentionally a dick about it, and very intentionally and consciously has mixed his film so even on most cinema setups, you have to strain to hear them clearly, because he delusionally thinks (or thought, he seems to have changed his mind somewhat with Oppenheimer and after the negative reaction and huge mockery for it with Tenant) that this "enhances the experience", rather than just screwing over a large part of the audience who are watching the movies in less-than-ideal theatres, have minor hearing issues which don't cause problems with other films, at home, and so on.
It's a slightly similar issue with high-end TV shows (including BBC ones here) - many seem to be mixed on the assumption that you have a 5.1 or better surround system that is fully and correctly set up. Now, what gets me is - we know that's completely false - almost everyone (I forget the exact figure, but it's very high, like over 80%) is watching TV with the sound coming from the TV's built-in speakers, or on a laptop or tablet or phone with terrible speakers or low-end stereo headphones. On top of that, many people just don't turn the volume up, because the mixing is such that, to hear the speech, "loud" sounds have to be VERY LOUD, and depending on the speakers, potentially even distorted. This is part of why so many people listen with subtitles on now.
If you have good quality headphones, or a proper surround setup, or even just a good soundbar, you probably won't come across the issue.