Feedback:User/Blessed Spectre/Deadly Haste

I've tried many times to make Deadly Haste viable in a build. Over and over I realise there aren't that many half-range skills that Assassins can benefit from. Considering that, why not do a re-work of the entire skill? When I read Deadly Haste I think of someone attacking fast, with deadly precision. I suggest the following change:

Enchantment spell ( seconds). You attack 25% faster and deal + damage with your attacks. You lose health each time you hit with an attack.

I believe this would be an excellant rival to Way of the Assassin which is currently the only IAS skill available to Assassins. I was considering either having the bonus damage be untyped/shadow damage or make attacks unblockable... but wasn't sure if that would un-balance it.