But wouldn't that potentially result in a too sudden dramatic drop in difficulty - thus destroying the balance?
(I already experienced such an annoying difficulty drop in FO2 when I got my first gun, after many hours of struggling to keep my character alive with a spear.)
For myself... it doesn't matter. If you acquire a gun, fighting others becomes easier; If they have no gun, it becomes trivial ~but it sure would seem silly if that were
made to be not so.
IMO the best method is still the careful incremental difficulty increase as the player travels farther from their point of origin [on average]. In practice, the player walks into a town of yokels armed with pipe rifles and a few melee weapons... further on he finds a larger town where guns are more prominent and the fights more deadly; farther still and he encounters a secluded base ~of enclave, super mutants, robots, auto-turrets... where the enemy has heavy weapons and hard armor of their own, and those big guns are not so effective against the new threat. If the player strays into tough territory, and they make it out alive ~then they know better than to roam those regions without heavy armor and weapons. :shrug:
How about this... Another thing that I think the Witcher got right:
What if the character could carry only a very small number of weapons?
Like if he could carry only one large gun or melee weapon + one or two small guns or melee weapons + the armor he's wearing.
Fun trumps realism no? Silly as it was, I never got tired of watching the PC pull a 3' minigun out of his hip pocket, nor felt odd watching them not get tossed on their butt for trying to use it. This is a real sense of loss with FO3, and its increased level of detail (in everything)... That just no longer works or feels right once you put in Havoc physics and close visuals.

The point is to strike a balance I think. Perhaps something that adapts to the player. Do you use a lot of ammo, in that case you will find more ammo. Are making your shots count less ammo.
Personally I liked it when the items and caps I had, had to be traded for ammo and supplies. When you came into town hoping to sell your loot for that extra ammo.
I'm against dynamic leveling (both in NPC's and economic effects).
Perks like scrounger really annoy me, for basically rewriting the past to provide you with additional loot that would otherwise not be there.
*example from the wiki*
For example, a single ammo container can occasionally yield as many as 28 missiles if you have this perk.
I'm not talking of FO3. Fallout 1&2 even with it's weighted ammo, allowed you access to an amount of ammo an armory would be jealous of.
Que!? (insert pear with mouth here). Ammo sacristy =/=> FO3 dialogue system.
The point wasn't about mastering all skills. It was that an extremely rare ammo system (ala Mad Max) would deter people from using and investing in gun skills.
Those comments were addressing more than one post at a time.
The problem with this is that it limits your character design choice. Tagging skills in unknown skills is never possible. And you have to wait in investing in a skill until you've come across something to learn it from.
Should it be?
In Fallout [1 & 2] your PC is the next guy the Overseer/Elder picks to send out for the chip/GECK. Your PC is a typical vault guy/tribal with a past that has undefined specifics; By contrast, in FO3 your entire life is laid out, your family, friends, school, aptitudes, and even your experience with firearms. In FO1 the PC may plausibly know just about anything, while in FO3 the PC is overly defined, and the idea that they can tag energy weapons, or big guns is kind of absurd.