I used to enjoy him mainly because of how cheap he is. and Also that he has a powerful impact on the game aswell. so i found him white usefull but i wouldnt go stonekin just for this card though (probably because i never really liked frost.)
I don't like it i love it. I did not really notice the low health since My tank most of the time took the damage. Its attackpower was Also great. and i really enjoyed its speed aswell.
I used to use overlord instead of him in PVE. But the few times i tested the lost warlord i found him quite good and amusing since he had better stats. But most of the times i used overlord over lost warlord since the overlord could give his health to other units which i found quite helpful. And the lost warlord is also needed to have 2 fire and 2 frost which will destroy the possibilities of using other faction cards, while the warlord only needed 2 shadow orbs which made it possible to go for other faction based cards. The warlord also costs 40 power less than the lost warlord. However i enjoy both cards and find this card very good to use.