Perfect D Clone char is?...

[Obi2Kenobi]

It is useful even at level one (although I will admit that it is much more useful for Paladins relying on physical damage than BH). It is basically immune to undead (unless they are ranged, in which case it just stuns them every pulse, delaying their attack). Vigor might make Meph/Worldstone runs "faster", but in HC, if dolls are around, it's better to be slow than dead (prevents mercs from killing them on top of you).