This question has been asked a number of times. If you search the forums, you will see that there are a number of mods, which, in a logical manner, alleviate the threat of being OP in New Vegas. Adjusting settings in mods like Project Nevada can further solve the issue. My way to solve the problem was to set the game so that leveling up no longer automatically raises your health and is tied to Endurance ( same for npcs), stopped skills from affecting the amount of damage dealt with a weapon (and instead affect accuracy and efficiency), and installed the mod that has your DC equipment looted from you by one of Benny's accomplices (he will use your gear, until you get it back).