I play the new shadow Warlock and I had the problem that I would like to have Leech on the LMB and with a bit of research I have 2 addons tinkered here which accomplish exactly that.
With me both addons work.
The two addons work properly I have applied the addons as follows.
-FIXED : Moved REPULSE to 4 as well (by mistake)WHOOPS~! its back to normal now... (ice only)-