I actually just played against an Olaf top as Mundo top and screwed up early game allowing Olaf to kill me under tower. He rushed executioner's calling + his corrupted flask. Now maybe his build is kinda bad lacking stats but I quickly realized I could still bob him hard with q and e even though he's Olaf (whose a strong laner)
That executioner's thing is really only gonna affect Mundo's ult, the rest of Mundo's dmg is still pretty absurd.
Tho perhaps it is bad he rushed it so early. But it made me realize that item is not so big of a deal, at least for Mundo imo. (Now when I built executioner's after my mr item as Gnar vs. Vlad it made a gigantic difference tho and I could just train Vlad down)