nothing prevents you from having scourge and a t4 version of torment pulse, just because scourge exists doesn't mean there can't be another item, otherwise half of the items in the game wouldn't have a reason to exist, since there are several items that do the same as other items.
The enemy would have to have 3k+ health for the scourge to do the same damage as the torment pulse. Scourge's only advantage is spiritual resistance, in terms of damage, Torment Pulse is better.
How about a hero like Grey Talon, an archer who stays far away shooting arrows but gains souls by killing enemy heroes, like Vindicta. I find Grey Talon's arrow-shooting gameplay fun. There could be more heroes of this genre, with diverse abilities, and I think a bounty hunter archer would be a...