Buff Or Add New Weapons

Even if you end up buffing them, they will become obsolete as time goes on, considering that you eventually unlock better, more powerful weapons.
I would agree that some of these weapons are unreasonably weak toward the enemies, but I suppose that is the whole point of the game. Making it so all the weapons would be powerful enough according to their level is definitely easier said than done, knowing that it might create some balancing issues of its own.