I only played a little of NV and spent most of my time with FO3, but this is an attempt to marry those systems a bit, and make the Gun skills a bit different by making them affect more than damage and spread (spread on FO3 looked especially bad because the gun stays stationary but the bullets will fly completely randomly).

Skill Changes

In NV, Big Guns was removed for Survival, so you had Guns and Energy Weapons. I would instead bring back Big Guns and drop Energy Weapons by merging it into Small Guns and Big Guns. To me it makes more sense to have Small Guns and Big Guns because a Minigun is vastly different to use than a 10mm pistol, but a 10mm pistol would be similar in aiming and firing to an energy pistol, except for recoil. I would also push a select few guns from Small Guns/Energy Weapons into Big Guns, namely the Sniper Rifle and any large Energy Weapons. The main reason to push the Sniper Rifle into Big Guns would be to give it a .50 round instead of a .308. Make it hard to use but give it a powerful punch. And because the regular Hunting Rifle is already really useful as a Small Gun.

Aiming

Of course you will be able to shoot from the hip and of course you can aim down sights. This just makes sense. It makes aiming not awful like in Fallout 3, where you either use VATS or you mash the fire button until it dies, wasting ammo. And it still enables you to pump a Ghoul full of lead when it jumps out from around a corner. However, I think the Gun skills can have more play in this than in previous games. In previous games the skill basically influenced damage and sway/spread, and that is fine. But I would put a little more into this.

The main things I would have the Gun skills influence are:

• Weapon Sway - Similar to the previous games, this would affect weapon sway in all situations. Hip fire and ADS, when standing still, crouching, prone (maybe?), walking, and running. Depending on the way you are aiming and moving, your weapon sways more. This means less accuracy. High levels in the appropriate Gun skill reduces this effect.
  
  By the way, I'm talking excessive sway at lower levels. Levels 1-25 would be akin to a 9 year old trying to aim a gun on their own for the first time (don't give 9 year olds guns to see a comparison). 25-50 would slowly build to the sway you would see from an amateur but competent gun user. 50-75 you would be at skill levels you would expect of an experienced hunter or someone with extensive training. Once you approach level 100, the gun will hardly sway. You're basically at Rambo levels of steady with a gun.
  
• Recoil - This ties in to Weapon Sway. Not a lot to say here other than low levels means a lot of recoil, taking longer to line up shots. This could tie in to the caliber of the bullet fired, where a .44 will have a higher recoil compared to a lower caliber, and could even out at higher levels in the Gun skill for that weapon. The exception for this would be some Energy Weapons, depending on the type of shot.
  
• Accuracy (VATS) - This would basically not change. More skill = better hit chance. The only thing I would change is make so there are diminishing returns on repeat shots to simulate recoil reducing accuracy on successive shots. As with Recoil, this gets lower at higher skills.
  
• Reload Speed - Reloading a weapon (especially when you have to load individual rounds) can be a pain, especially if you are not good at it. Lower Gun skills could result in a slower reload speed overall, with a chance to screw up the reload animation, which would just be a secondary animation that is slower. Little things like attempting to put a handgun magazine in backwards, jamming your thumb when reloading a shotgun, etc.
  
• Damage and Critical Hit - If anything I think this should be fully determined by weapon used and where you hit. Being skilled in handguns and shooting someone in the leg in the same place, with the same gun, from the same distance, would not do more damage than if it was done by an unskilled person. Make the Gun skills affect your actual ability to shoot guns well, instead of somehow making bullets do more damage. Although I would be okay if it still did this.

Weapon Modifications

Of course these are in. Suppressors, scopes, you name it. You can find them, buy them, craft them (some anyways, like you can tape two magazines together for increased reload speed).

I think that is about it, but I could have sworn I had a whole other section I cannot remember. I just want an amateur with guns to feel like an amateur. It bugged me that in FO3 I only ever played with a BB Gun as a kid, yet as soon as I get a handgun I'm shooting like Wyatt Earp in his prime.

To me personally, I liked having guns separate from energy weapons.

Me too.

I wouldn't mind Big Guns making a return, but not at the expense of Energy Weapons.

The skill is more than just "point and shoot". There are many differences, such as the proper care and feeding; for example, dealing with uncooperative microfusion cell electrode contacts is different from clearing a stovepipe jam.

And as for "bringing back Big Guns"... Big Guns was a pointless waste of a skill. The skill was entirely dependent on a tier of weapons that were usually total overkill in anything other than a mosh pit of super mutants, and usually had rather expensive ammo that it went through rather quickly. Having them require its very own skill just negates any practicality it even has for when it *is* situationally appropriate. Best to spread them into Guns, Energy Weapons, and Explosives to remove that expense of skill points and have strength/skill requirements for optimal use.

I have a feeling that the "Big Guns" may end up requiring power armor to use, just judging by the sheer bulk of the minigun being held by that power-armored soldier in the flashback to the final moments of pre-war times.

I agree about Big Guns. I liked how they did the heavy weapons in NV; putting them in their respective categories.

And on a more jestfully antagonistic reason why Guns and Energy weapons should be separate.... It'll be a cold day in hell before I let my fancy amplified light weapons and atomic-powered plasma guns get categorized with backwards primitive firecracker-powered slug-flingers!

Don't get sassy!

Sure.

And then we can merge Melee and Unarmed into Close Combat.

And Lockpick and Sneak into Infiltration. Hell, we've already lost Steal to Sneak, why not Lockpick too?

And Speech and Barter don't even need to be skills! Give 'em over to Charisma.

Or alternatively, how about we don't minimize the already lacking skill list?

Point I'm trying to make is that while it logically make sense for Unarmed and Melee to be different skills gameplay-wise in the current format they are practically the same damn skill. And Charisma really is a worthless stat and have always been because it shouldn't/doesn't want to intrude on the territory of the skills. But if we have a dialogue centered stat then it should take precedence and so wouldn't it make sense to merge the two with Charisma? Or at the very least merge the skills with one another? As to Lockpick and Sneak, that might seem like an extreme example but I don't think so. Sleight of hand and being able to tip toe around are two completely different things and they still merged them together. So why not just throw Lockpicking in with it?

My point is that we shouldn't be merging skills at all. We should find a way to flesh out skills and differentiate them from one another. And so far? Energy Weapons and Guns do handle differently. But I think they could be even more foreign from one another. What doesn't help is to just smack the two skills together.

You say you want Small Guns and Big Guns but what about Medium Guns? See a pistol or revolver or laser pistol will handle very differently from an assault rifle. And an expert shotgun user wouldn't be able to just pick up a plasma pistol and use it with the same amount of skill. Even among the heavier weapons it becomes drastically different. An Arch Lightning (?) is not the same as a Minigun, which is not the same as a Rocket Launcher, which is not the same as a Tesla Cannon.

If it is for gameplay reason that you want the merge then there are way better ways to distinguish the two already existing skills.

If it is for logical reasons then we don't need a merge, we need splits, lots of 'em.

We can't have a system which "makes sense" without splitting everything up into tons of different skills.

Finally, they do what you say then we still end up right back where Big Guns was an issue again: It is too much of a specialized skill.

If you invest into the skill then either you 'have to' invest in another combat skill or you're stuck using heavier weapons exclusively.

Having to whip out a Minigun to deal with rats.

Or getting bogged down with weight because you need basica ammo to survive for a while.

Or simply not having access to any heavy weapons at the start of the game because they're heavy weapons and they're meant to be really hard hitting.

And then having to wander around with that 'one' heavy weapon you managed to find, which is too expensive to repair at repair NPC's and who's ammo isn't all 'too' common.

Yeah, let's bring back Big Guns. What could possibly go wrong?

[edit]

Besides, a rifle and a laser rifle are not the same thing.

They reload differently, lasers have no recoil (or shouldn't have any recoil), and lasers are meant to be instant beams of energy meaning they don't have a bullet trajectory over longer distances.

A plasma rifle is even more different because its projectile has a way slowe trajectory than any firearm.

Tesla and Pulse weapons are basically electricity, electricity is damn spastic and would require a skilled professional using them.

Flamers too, are completely different from either of the three, EW, Guns and Explosives. But have to fit in somewhere.

The skills are just meant to be a general knowledge of all of its category.

Perks are where you should be able to specialize and excell.

I personally like how new Vegas did it better and would like to see that return at least in regards to the weapon skills. Also, I'd like the gauss rifle to move back to guns and get rid of this energy weapon nonsense.