I refer to of course the E3 presentation when you see the Mr Handy.

Slightly disappointed that the protaganist's reflection wasn't shown on it's shiny surface

and was wondering if this could be resolved via mods?

Anyone noticed that too?
It isn't a very big deal, but I hope they are able to correct it before release. (or a later patch)

I have no idea of the difficulty something like that takes, but it was one thing I noticed right off from the E3 demo. Not really a big deal to me but still.

Realtime reflections are fairly resource heavy, not many games actually utilize them because of this reason. The game is now using PBR - Physical based rendering, the latest game to use PBR as a good example would be Witcher 3.

The reflections/refraction off of materials/objects should be much better this time around, if only because of the use of PBR. What you are wanting is something completely different and I'm not sure a Mod could do the trick. I might be wrong however, then again, I have yet to see a good example of this done via modding.

Ooo i've heard of PBR, but thats from Star Citizen.
I didn't know that Witcher 3 uses PBR too lol~

Yup, if you have the debug console installed, take a look at the armors and weapons up close, you can see how much more realistic and detailed the materials are. Leather looks like leather, metal alloys differentiate and reflect light etc. I noticed FO4 was using PBR as soon as I watched the trailer, take a look at the armored Vault suit for a good example of PBR. ETA - Codsworth's metallic surface compared to FO3/FNV Mister Handy.

Not gonna be a lot of shiny 200 years after

PBR is 80% buzzwords and hype. Most of what it means is that now we have higher resolution normal/specular/diffuse maps instead of the 1/2 or 1/4 rez we had last generation. Throw in some sub-surface scattering and you got 90% of what differentiates current gen graphics from last gen.

Reflections, beyond simple specular and diffuse highlights, are still evidently just simple cubemaps (either pre-generated or rendered on-cell-load). Real-time reflections are still quite an expensive proposal and beyond the capabilites of modding unless one digs deep into the renderer.

https://www.marmoset.co/toolbag/learn/pbr-theory is "just" a different way of doing things, and (especially with the roughness/metallic workflow) it's impossible to "get it wrong". The system will handle energy conservation automatically. Old ways of writing shaders easily allowed making implausible materials, such that i.e. diffuse + gloss exceeded incoming light, or inadvertent texturing made it happen by accident.

The bad thing is that pretty much all texture assets have to be thrown out the window and recreated from scratch. This may actually be bad news for modders who rely on old textures with effects baked in. Old diffuse color for wood may no longer work (due baked in effects that used to be okay), and you have to use a https://seblagarde.wordpress.com/2014/04/14/dontnod-physically-based-rendering-chart-for-unreal-engine-4/ to pick good values for i.e. roughness.

A PBR based material will look natural in any lighting condition thrown at it. Other types of materials may still have to be used for 1% of special materials. But 99% will be covered by a very generic type of shader that basically can't show anything hideous no matter what inputs you throw at it - it will look plausible (metallicness should be very high contrast though).

Physically Based Shading does not equal Physically Accurate Shading. A metal will (roughness/metallic workflow) be a base albedo color going to reflection color (as dictated by the metallicness value) rather than be based of complex fresnel for conductors (a custom facing gradient will be the best bet if allowed not to be driven by textures). Fresnel mix (diffuse/gloss) is usually driven by Index of Refraction, but this value is "arbitrary", or difficult to control in a deterministic manner (hard to guesstimate what you will get as an artist), and is often replaced by a facing blend curve to some fixed power (faster to compute) where artist controls its minimum value with a direct meaningful number. It's not more realistic, obviously. The power of PBR comes from less controls in the shader for the artist to mess up

I wouldn't go as far as calling PBR buzzword and hype. It's fully possible to achieve awesome results without it. It's just that while using it, it's easier to achieve good results without spending too much time tweaking, hence you will get more good quality and reusable assets in the same time frame. It can't do everything, but will easily handle 99% of what typical gaming assets require.

That said, I do prefer other systems if memory is not an issue. But for game assets, sure, PBR all the way (until something better comes up).

Some interesting video about physical plausible shading here: https://www.youtube.com/watch?v=b8LFBX4x4qE