Apart from Seraphim, which units actually have Hit and Run? Also if you are leaving combat shooting then re-charging then you are going to take a bit of damage from overwatch too, in most cases not much but still.
Me: To be honest im amazed there isn't a chaos god of not revising or at least chaos god of procrastination
MidnightSun: There will be, when enough people do it. Y'know when the Eldar were all engaging in their hedonism and Slaanesh ripped open the Eye of Terror with his creation? Slaanesh will have NOTHING on the God of Procrastination, and his vile minions will carve the galaxy asunder in a thousand year reign of blood.... Tomorrow