Only "...smack it with a hammer" if you want to buy a new switch! The weak LED's are probably really neon bulbs, as LED's will either work, or not work and aren't as suseptible to voltage changes as neon bulbs are.

The reason for the slightly dimmer bulbs could be because the plastic lens has gotten dirty, or that the bulbs have moved out of their holders inside the switch.

Provided the switch is still functioning properly, you can disconnect the power to the circuit and remove the switch to see if the bulbs have been dislodged from their mounts, or are lose, etc. Otherwise, if working OK, I'd recommend leaving it be.

If your switch does have the LED's on the side, you might find that the mini circuit board has gotten pushed out of its' proper mounting position and by resetting it back on the faceplace to the proper location, could make the lights brighter again.

Hope you find this Very Helpful and best regards!