Quote Originally Posted by W00by View Post
It actually already can target friendlies, but you have so little time to use it that you definitely don't have time to move your mouse (or god forbid you're on controller), target an ally, use Slither, re-target the boss, and hit it again and maintain full uptime easily. I agree that an untargeted slither, perhaps similar to Picto's Smudge or Dancers En Avante would be a lot better. Or perhaps something similar to ninja's Shukuchi?
I use a mouseover macro for all my ally-targeting movement skills (VPR, MNK, SGE, BLM) and recommend it highly to any other keyboard users:

/ac "Slither" <mo>
/ac "Slither"

If I'm moused over a target, it'll go to them. If I'm not, it'll go to my target. It does force you to be conscious of your mouse position, but you'll never miss a GCD once you have that part down.