Critical hits could be amusing if you're the person to actually strike them, but if you're on other end, though, it could be quite frustrating. I've got struck by these things many times while battling online competitively and in-game, and at times, wound up losing matches because of them; they could ruin strategy for you and opponent equally, and could make stuff more complex. Personally, I'm not to fond of this feature, but it's definitely needed to add more realism. Without it, everything would simply seem robotic, and, well, boring. I'm pretty glad that they've been able to think of such a system, really! I understand that many people aren't too fond of it, but we've all gotten used to it by now, haven't we?