First, examine how you currently get all the staples from the pad off the floor when pulling up carpet. You might use a pair of pliers and simply pull them up. You might use a staple remover; it works faster than a pair of pliers, but it is still a lot of work. I prefer something faster and easier. After all, time is money.
Here is a suggestion to help improve the look of floor vents. Put tackless all the way around the vent. This gives a solid base for the vent covers to sit on, as well as providing a cleaner, finished look. If you are concerned about stretching over the vents, either pound the pins down or face the front and the back toward the wall.