It's just a suggestion, but to make it fairer for the person that loses initiative why not let, for round 1 only, that he gets back his full defense/resistance/damage reduction stats? That way the attacker have the upper hand with initiative and still have it on round 2 since still starts first, but at least the defender don't get owned in a second by the enourmous difference in power a barrier up or an incapacited ninja will give him.