A lot of what your rotation should be depends on your personal play style. Even on the beta servers, I prefer drain hunting over tanking, so I choose my sequence to provide the lowest threat to begin with. Send pet in, wait for him to get aggro. Then Siphon Life, Corruption, CoA, UA, Haunt, Life Tap, Drain Life. I don't draw aggro, mob dies. Sure, drain tanking is faster - but I save time by not needing to get my armor repaired as often.
If you drain tank, your rotation would be different, since you want to grab aggro away from your pet. The same for other play styles. the rotation while soloing should reflect the way you play and not be a "something for everyone". DPS isn't the only criteria for soloing.