if I was in charge...

If I had Creator powers, my first redesign of human physiology would be to include on/off switches.

Hunger, on/off.
Fertility, on/off.
Hearing, volume control at least.
Sense of smell, on/off.

Perhaps also some sort of self cleaning function, inner and outer, like ovens of the future.

And active regeneration of skin, nails, teeth - and organs while I'm at it.

Also follicular control would be nice. No more unwanted body hair, and ready made extensions.