I mean considering the secondary effect possibilities I think it's justified. But yes this goes against typical single target spammable cost standards.

No, OP is right in a sense, I wrote feedback about this on their scribing page.

Ranged instant spammables have a standard of 2700 cost, 2091 damage, 28m range. You can find this on Silver Shards, Force Pulse, Cliff Racer, Swallow Soul.

Sometimes the ability ranks up in damage or cost reduction.. or in the case of Silver Shards, has a +10% damage passive... But at minimum, they all start out the same way.

Note: All stamina skills have -15% cost reduction either built in or through a passive. Eg. all martial weapons have -15% cost passives, Fighters guild has -15% cost passive. In the case of Mages guild and Psijic Order, their -15% cost apply to magicka abilities as a unique feature to those guilds, it is not mandatory. The reason for -15% cost on stamina skills is because you are required to use the same resource as the one you use for core combat abilities like dodging, blocking, and sprinting.

Back to Wield Soul. It has 2700 cost, 2024 damage, 28m range. The cost is right in terms of magicka, but it's wrong in the case of stamina, it should have the -15% cost baked in because there is no skill line passive for it. This is how morphs for stamina vs magicka work in classes for example. Compare Flame Skull and Cliff Racer morphs.. or really anything that goes stam vs mag.

To top it off, it has 3% less damage and no skill line passives. It's puzzling how they missed this.

Before you say it's deliberate, please refer to Trample. The mag damage using magicka cost is 3240, the physical and disease version cost 2754. This is an example of a line without a -15% stam cost passive, that had it baked in.