But I'm sure Bethsidian has its limits and reasons for AI and difficulty settings so I'll just let it slide this time
Exactly, we let it slide this time with FO3, but now Obsidian is left holding the bag!
Programming a more intelligent difficulty system wouldn't have to be much more complex than changing the enemy HP variables like they did in FO3. Each enemy in the engine by necessity already has certain variables attached to them - area of awareness, accuracy, weapon damage, etc. Sure, AI tactics would be more difficult to change, but if you changed those three variables I mentioned, that would get you by in a pinch. As for ammo or stimpaks and drugs, just make those markers when placed in the engine, with the difficulty setting determining the chance of them appearing in-game, and how much there is if they do.
For instance:
Very Easy - Stimpak is always there
Easy - Stimpak is there 90% of the time
Normal - Stimpak is there 50% of the time
Hard - Stimpak is there 25% of the time
Very Hard - Stimpak is there 10% of the time
They already have enemy markers that essentially do the same thing in the CS.
Sure, you would have to experiment to get the exact ratios of chance that work best at each setting, but you get the idea. Similarly with item counts for ammo:
Very Easy - 30 rounds
Easy - 25 rounds
Normal - 15 rounds
Hard - 10 rounds
Very Hard - 5 rounds
You could even mix and match the two approaches, or randomize the amount of ammo within certain limits, like for Normal Difficulty you may find between 10 and 20 rounds in a container, etc.