Haste is a pretty useless stat for Enhancement. You'd be giving up an awful lot to spend GCDs you don't have on a spell you don't need. Nevermind the fact that we're talking multiboxing. In order to make LvB useful, you'd have to have some top end gear and the freedom to manually cast only when all other abilities are on cooldown, and it would also mean you're losing out on white damage and potential WF and MW procs....a further DPS loss.

Use a multistep macro. No one has rotations anymore, it's all priority casts and you can't account for priorities in a tiny macro anymore.


Multistep macros with ISBoxer
Multistep Macros with HotKeyNet
Multistep Macros In Game