looking at the break I would say that it was not the fact that it was a stick tang that caused it.
Likely cause was:
1) the tang wasn't glued in. this means it vibrates and then crack the wood when 2) happens (I've done this to an old billhook!)
2) the blade was struck by a batton
3) a crack was in the wood already and the loose tang opened it up upon impact.
Full tang on big blades tend to transmit shock into the hand more easily, the scales seperate a little (due to the tang flexing) which then lets rust in and you get a nasty pinch when chopping.
Those are just my experiences though
On the plus side of the broken handle, it lets you customise it