Fallout 4 has a lot of strange artistic design choices, some better and some worse than F3/nv. The scorpion design exemplifies what I feel. The F4 version is too stylized and does not fit the games tone as well. I find the texture and model work in the F3 version to be superior

Combat armor in F4 is an offender. Why does it look like that? why is it that color? They interpreted the power armor designs well, why not this? The community seems to agree that it looks ugly, as there are have been a few mods to replace it with the earlier version.

The fallout 4 "assault rifle" nonsense, someone on the design team was too hopped up trying to make it "SO 50s" F3 and NV had reasonable rifle designs that fit the setting. A lot of people don't understand that you NEED "mundane" designs to make the unconventional stuff stand out

What F4 does do well are the robot designs, clearly they were what the design team gave a shit about. They all have modeled internals and surface paneling that can be damaged and destroyed as you fight them. makes them feel less like bullet sponges compared to organic enemies.

Robots and the early synths are the most fun enemies in the game to fight, having more reactions and damage states than any other enemies. They have some genuinely fun details (sentry bots will slowly walk with their legs if their wheels are destroyed, weapons can get destroyed)

Assaultron is clearly the standout. I would go as far as to say it is fallout 4s MOST memorable enemy. Well animated, dangerous to fight. As a robot being a bullet sponge is more acceptable. Relentless enemy too. Its legs can be destroyed and it will crawl after you, nice detail.

Theres probably more I can say but this is only about the art design. Seems like they had different designers each working individual things so a lot of designs feel incongruent. (some insects are realistic and grotesque, while some like scorpions and crabs are cartoons)