I don't agree with giving a shotgun, especially a double shotgun, because they're better for lost souls. Shotguns are good against them, and so are ammochained plasma rifles, and so are blademasters. The double shotgun has likely spawned like eighty times by the time you've reached the City, anyway.
I do agree with not dropping another BFG, especially since Halls of Carnage is so easy. What I'd kind of like to see is perhaps an armory-like spawn - more than one random weapon shows up scattered with the ammo, along with a higher chance to be exotic than normal.
The skullcrusher is right out. Melee is already wonderful with just an appropriate master trait and a chainsaw.