Here's something to consider when tossing around balance ideas.
You can't just buff all weapons. There is a concept known as a damage economy. This works just like other economies. If a company gives all their workers a raise, then they have to raise the price of the goods they are selling. The new cost of the items means the workers all need raises to afford them which, then means the price of the goods have to be raised. Inflation, in other words.
Similarly, if you need to keep a game challenging, you cannot just raise all the weapons because then all the enemies will require buffing. Then we are caught in a viscous cycle of inflation again. The trick is to keep the game challenging while ensuring all weapons have equal footing. Common weapons for Bronze, Uncommon for Silver, and so on.
So, no...you can't just buff them all. It's complicated and delicate.
Cheers