The incredible power of "The best" guns in games are typically limited by Ammunition, the ease of acquiring said ammunition, and unique downsides. Downsides such as "This minigun takes a second to spin up before it starts firing" or "This solar satellite laser can only be fired once per day". High weight of the heavy weapons (and often heavy ammo) also counts towards your maximum weight limit. In Fallout, Weapon skills exist to encourage a themed playstyle, and perks to facilitate this are locked behind skill requirements. You can be the Silenced Pistols and Sneaky guy, for example. Or the long-ranged sniper-rifle guy. Perks boost your crit damage and sneak attack critical damage, they're what you want. In addition to the Weight penalties, there is the Strength Check system where you need a sufficiently high Guns skill and Strength rating to use a gun effectively. So a Heavy Weapons user NEEDS at least 6 in Strength where a crit-focused character with plentiful and cheap insta-killing silenced pistol crits would get away with 1 or 3. These are points that typically have to come from somewhere else in your build, harming your ability to go for 10 AGILITY or 10 LUCK. As it stands, if a player gets 100 guns and finds a really big and good and rare gun with highly limited ammunition, he'll be terrible with it if the game has a separate Big Guns skill. Even if it's supposed to be a big reward, an amazing unique weapon and one of the best in the game, for everyone not specced into Big Guns it is worthless. He'll need to skip putting 100 into Sneak or Speech or Survival and pour those points into Big Guns before the "Big amazing gun of coolness" actually becomes better than his tiny cowboy revolver. And it's not like there's a Big Energy Weapons skill. If an Energy Weapons player finds the ultimate big cool energy weapon gun and it's classed as a Big Gun, his Energy Weapons build and collection of Energy Weapon-enhancing perks can't affect it. Unless the perks are programmed to count this Big Gun among its list of acceptable Energy Weapons. Typically, Big Guns aren't something you get for a while into the game. No "Sucky Big Gun" exists for low-level players to let them see if Big Guns are something they'd be interested in. And Fallout doesn't have a lot of Big Guns-focused perks. FNV might have more Revolver/Cowboy Weapons-themed perks than the entire franchise has Big Guns-focused perks. The Melee Weapon skill covers all melee weapons, including sledgehammers and knives alike. There is no Two-Handed Melee Weapon skill. Every melee weapon besides the power fists and boxing gloves are counted under the Melee Weapons umbrella. The Guns skill covers automatic and semi-automatic pistols, pipe weapons, revolvers, small pistols and big pistols, automatic rifles and semi-automatic rifles, sniper rifles, and more. The Energy Weapons skill covers Laser and Plasma weapons of assorted sizes, speeds, and damage ratings. But the Big Guns skill only covers big guns. The biggest minigun, and maybe the biggest Energy Weapon. Big Guns are already rare, and typically have their use limited by rare ammunition. As it stands, the Big Guns skill is a massive investment for an incredibly minor benefit that makes you decent with, rather than terrible with, an impractical and limited type of weaponry. But Fallout 4's way of throwing Skills out the window to be replaced with mediocre perks, that was wrong. A wrong move with a decent idea behind it. Fallout NV's perks designed to enhance an aspect of a playstyle were superior to Fallout 4's "Improve this class of weapons" perks. And not just because F4 put "Presentation" before function and overly limited the number of perks in the game, when you can take them, and what perks you're allowed to go for at what level. Going the "Big Guns Perks" instead of "Big Guns Skill" route allows players to spend their limited perk slots specializing in whichever aspects of Big Gun usage they want. Want to reduce a gun's unique downsides, increase fire rate, increase damage, and so on? Separate perks can do each of these, letting you fix the downsides of Big Guns or enhance their strengths further, or do both at the cost of more perk slots. What would the franchise lose if the Big Guns skill was permanently replaced with a set of perks specifically for Big Guns? What would it gain?