people talk about animation lock but to me animation lock makes perfect sense, it happens on doing an action. Choose when to do you actions carefully. To me thats basic game design, If you do something special you take a risk. Choose when to do you actions, or think strategically.
lag is a different issue, but to be honest i think he died less from lag, and more from not knowing how to handle ifrits skill sets and patterns. He even admitted as much. the primary lag related skills dont even occur in the part of the fight he got up to.