I’d suggest rather than stunning the target, the target gets a -10 reduction to their melee offense and defense for a turn to represent being off balance.
Now this is a good solution. Doing a debuff on enemy for their stats while doing small damage and stamina damage. Perhaps a debuff on everything is the best. Reducing their melee and range atk and def, demoralizing and maybe even taking few ap off. Perhaps reducing damage or improving damage taking and chance of head hit. A mix of all or some of stats could be enought to make this skill work.
