I don't think UD will be the best, but it won't be useless anymore I wish I had money to go back to undead./ I just love how ud casts, the way they move screams "DIE MTeRFKeR DIE" !)
But until we get the complete loot list for t14, it might be possible the 30% haste cap will be impossible to reach even for gobelins, so yeah ud might be best.
Also i just noticed but they deleted mind surge with no word on it on mmo! Haste value went down;s I would be glad if it were replaced by something good but the fact its gone without anything to replace it feels kinda cheap.