I think the aggro reduction suggestion would probably suffice. Tanks are responisible for boss positioning, grouping adds, etc. The exact spot they plant their feet is 9/10 where their feet need to be planted, and if its used on a DPS, all it does is safety net them incase they may have grabbed aggro or step in the wrong spot. As far as it being an irregular use of the skill, I agree it is very very uncommon, but I think its best to address the loopholes or issues before they become commonly abused.