Absolutely Not - we as players have very limited information about the balance of the game and would in most cases get it Worse than the companies do. That said I do think there is tons of evidence of modders that Do make the game more balanced from a certain point of view. And these mods that do a great job at overhauling balance are Rare compared to the thousands of mods that add stuff without any sense of game play or game balance.
Remember we don't know the exact design goals of the game - they were never published. As such we don't know what "difficulty" level or "hardness" level they were attempting to hit as a baseline, and our own interpretation of what is "balanced" may be completely contrary to the goals they had in mind.
So while I will be the first to agree that the gaming companies don't always get the balance Perfect, I would argue that New Vegas does an excellent job on overall game balance as it is - especially given the awesome complexity of the game. We would get it horribly wrong IMHO.
Miax
