I would like to wear different parts of clothing instead of just 1 full outfit with a hat or helmet. I liked how in Oblivion you got different pants, shirts, and shoes, and I would like to see that in New Vegas. It'd also be neat to add things like aypocolyptic jewelry, such as tooth and bone necklaces, scrap metal wristbands, and maybe pre-war things like broken watches or tarnished wedding rings. It also would be cool if you could get tattoos.
There should be more clothing slots in this game. Morrowind was good for this, Oblivion and Fallout 3 were not. Clothing was too limited as to variety of what you could wear.
We should have slots for clothing, and some clothing have limited DR rates. This should include, Pants, Shirt, Hat or Headgear, Sunglasses/Eyeglasses and Shoes. There could be a slot for Gloves.
Armor should replace some, but not all the clothing slots. Shoes/Boots and Headgear should be Armor or Clothing but not both. There should be Armor pants and Armor Shirts that can be worn with or without clothing. Pants and Shirts can be worn under Armor so no need to remove those or put on a shirt if I take off my Armor. Unless I choose not to wear clothing under my Armor.
As for any Stat or Skill increases or decreases with each article of clothing, that is another discussion for another thread. Which we have around here somewhere.