I can't speak for difficulty level of Fallout 1 or 2 but 3 and NV where pretty fun. It's fun being an unmatched one man army but sometimes i wish there of a challenge without the need of self imposed challenges...

I think resources should be a little more scarce, you really shouldn't be able to have around 300 stimpaks or like 200 Rad-Aways. Ammo should be scarce as well. Players should really be encouraged to invest in building up a melee or unarmed skill set.

Radiation Sickness should play a bigger part in the game. I wouldn't say the perks that center around radiation would be mandatory but as it stands they are pretty much an after thought.

They could also limit the amount of weapons you can have on your person. You can still loot and collect weapons and have them in your pack but you have to specifically hot key the weapons you will use in battle and you are limited too like your main gun which would be like a Rifle, Shotgun, Big Gun pretty much any two-handed weapon. Than you have a side-arm which would be like a handgun, and finally you have a melee weapon or unarmed weapon. While in battle you can't open your pip-boy and switch to a weapon that is more favorable for the situation your stuck with what you equip on your person

How would you make the game challenging without destroying the fun factor?

Easy way to spike the difficultly, 1 shot kills on player character forcing stealth or death

I think there should still be an easy mode but there should make the Very Hard mode really hard like almost impossible to do.

Set to very hard, put on hard core mode, and go play dead money, and good luck my friend.

yeah that's what i am talking about make it more like Dead Money where you had limited resources and radiation or whatever the hell that was played a large part in the game. it was challenging but fun.

it doesn't have to be that extreme but yeah completely forgot about Sierra Madre. The game should be something like that...limited resources and the environment played a large part in the player's health

I think that there are a variety of ways to make fallout a much more challenging game, while not making it annoying. Annoying is Brush Guns, but perhaps one thing they can do is give NPCs a wider variety of improvised weapons with a good level of lethality. Crossbows, improvised air cannons that shoot spikes at MUCH more lethal power than the railway rifle. Chainsaws, more lethal traps, and generally a larger turn to focus on weapons away from Guns.

The other thing that could happen is greater bands of people together, and while this could be explained away due to system powers, I don't think that can be the case anymore. Raider bands can stand to be a bit bigger, people can stand to show more organization. In addition to greater numbers, they could stand to have more clever AI than the one they've used since Oblivion. Have enemies heal, have them take better cover, coordinate in flanking maneuvers, flushing out, suppression, the works. Take a page or two out of FEAR 1 for interior combat sequences, and try to find a balance between making areas meant to be shooting in, and areas that are meant to convey a place, and not a backdrop. Get creative, have unconventional traps in areas, make us think twice about entering that school or that metro tunnel.

I mean settig it to very hard and hardcoe can still make the game challenging even for high level characters.

The could set the resources could be set back to fo3 standards, because i remember it being harder to find a steady supply of ammo for guns seeing as how its was just in general less copious and you couldnt buy in bulk packs like fonv. I just dont think it should be taken down to to extreme of a level.

another way to add challenge, no weapons and no armor/clothes- bare naked brawling

Food was copious in Fallout 3, and I remember having several thousand rounds of 5.56mm, but maybe that was because of the Pitt. But then that leaves something like that in question, doesn't it?

We have a thread for all ideas and suggestions for Fallout games: http://www.gamesas.com/topic/1479722-fallout-4-speculation-suggestions-and-ideas-172/