Well, you are talking about our Blackhand, and this is WOD Blackhand. Their past is not the same.
Not even remotely confirmed yet. The other warlords share very similar histories (with minor differences) to our Azeroth, why should Blackhand be any different?
For one thing, the comic actually gave us a reason for his name (and, by extension, his new design most likely). Before that, he was just "Blackhand the Destroyer" with no significant backstory whatsoever. And I hate to say it, but I find his original design to be quite ridiculous compared to the WoD one.
But, opinions and all that. I can certainly understand why you would like the WC1 manual version better, Tauer, and I respect your opinion. I personally think the new Blackhand is better, not necessarily his furnace armor but at LEAST the gear he wore in the Blackhand comic. And his black, elemental-affected hand.

I'd be very happy with a version of this, preferably without the Doomhammer. That was a temporary thing anyway. It's like a blend between old and new, with no ridiculous WC1 manual helmet and no furnace armor. Plus the reason for his name is in full view.