Of the Guns, only the Cowboy Repeater, Trail Carbine, and Brush Gun were notably downgraded. Automatic Guns were almost universally improved. The Plasma Defender is a pretty strong EW and is most comparable to a .44 Magnum Revolver. The Plasma Defender really only loses out in health (the .44 Magnum Revolver is 2.5x more durable), projectile speed, and cost to fire (4 caps per shot vs. 3 caps per shot). Because Arcade's is a companion weapon, durability and cost to fire aren't really an issue.
The only thing that was "nerfed" about Boone was the Crit DAM on his Hunting Rifle. This is because of an engine bug that causes his beret (actually, any clothing item, but in his case, it's really conspicuous) to re-apply its bonuses every time you manipulate his inventory or toggle his melee/ranged stance. Very quickly, Boone's Crit Chance could be over 100%, meaning that his rifle would do over 100 damage with every shot. We're looking at fixing the underlying bug.
The guns are about the same the only thing that's been nerfed is the Sniper Rifle which was a dumb thing to do. I mean the Hunting Rifle's stronger, then the Sniper Rifle, really :shakehead:
The Sniper Rifle has almost twice the DPS and can be silenced. Weapons filling a similar role to one a tier above it will typically (by design) have one or two aspects that are marginally superior so players have to engage in more anolysis to decide which to use. If the Sniper Rifle were better in all ways than the Hunting Rifle, there wouldn't be much of a decision to make.