This is an RPG Maker MV plugin for displaying attack animations only if the attacker scores a hit.

attackAnimationOnHit.js

//=============================================================================
// attackAnimationOnHit.js
//=============================================================================

/*:
* @plugindesc Plays attack animation only if there is a hit. If miss, shows miss popup and plays miss sound. Applies only to physical attacks.
* @author robhav
*
* @help 
* Plug and play.
* --------------------------------------------------------------------------------
* Terms of Use:
* Free for commercial and non-commercial projects.
* --------------------------------------------------------------------------------
* Version: 1.0
*/

(function() {

var animateDisplayActionResults = Window_BattleLog.prototype.displayActionResults;
Window_BattleLog.prototype.displayActionResults = function(subject, target) {
	var action = BattleManager._action;
	var item = action.item();
	animateDisplayActionResults.call(this, subject, target);
    if (target.result().used) {			
		if (action.isPhysical() && target.result().isHit()) {
			this.attackAnimationOnHit(subject, target);
			
		}
	}
};

Window_BattleLog.prototype.attackAnimationOnHit = function(subject, target) {	
	var action = BattleManager._action;
	var item = action.item();
	if (subject.isActor() || Imported.YEP_BattleEngineCore) {		
		if (!item.animationId  || item.animationId < 0) {			
			if (!action.isGuard()) {
				var animaId1 = subject.attackAnimationId1();
				var animaId2 = subject.attackAnimationId2();
			} else {
				var animaId1 = -1;
				var animaId2 = -1;
			}
		} else {			
			var animaId = item.animationId;				
		}
		if (animaId1 && animaId1 > 0) {
			target.startAnimation(animaId1);
		}
		if (animaId2 && animaId2 > 0) {
			target.startAnimation(animaId2);
		}
	} else {
		SoundManager.playEnemyAttack();
	}			
};

var startAction = Window_BattleLog.prototype.startAction;
Window_BattleLog.prototype.startAction = function(subject, action, targets) {
	if (!Imported.YEP_BattleEngineCore) {
    var item = action.item();
    this.push('performActionStart', subject, action);
    this.push('waitForMovement');
    this.push('performAction', subject, action);
	if (!action.isPhysical()) {
		this.push('showAnimation', subject, targets.clone(), item.animationId);
	}
    this.displayAction(subject, item);
	}
};

var showNormalAnimation = Window_BattleLog.prototype.showNormalAnimation;
Window_BattleLog.prototype.showNormalAnimation = function(targets, animationId, mirror) {
    var animation = $dataAnimations[animationId];
	var action = BattleManager._action;
	if (!action.isPhysical()) {
		if (animation) {
			var delay = this.animationBaseDelay();
			var nextDelay = this.animationNextDelay();
			targets.forEach(function(target) {
				target.startAnimation(animationId, mirror, delay);
				delay += nextDelay;
			});
		}
	} 
};

})();