Ok so I want you to imagine that you are watching a movie. You finish the movie and decide to watch it again. This time, however, the movie is sped up a little bit so events occur faster than what you remember the first time you watched the movie. So, when you expect something to happen in the sped up movie, the only reference point you have is your previous experience with the slower movie. Therefore, you can make an informed guess as to when something is going to happen in the sped up movie but you are not 100% sure.

I feel this is the disconnect we are experiencing. This delay is the sped up movie. I GENERALLY know what is going to happen next but, due to how the server works, I am not 100% sure of when it will happen. I have a vague idea. Even though I know something is coming up, I still need to be ready to react instantly because it could either be behind the expected value or ahead of time.

You are right when you say memory plays a part in this. But I believe you are incorrect if you say reaction is not involved at all. It's like you completely ignore the memory aspect and assume that people will have no time to react as a result.

Let me give you a great example. Familiar with Twintania? There is a section of the fight where she flies up in the air and everyone has to stack (stacking in Twintania? crazy I know). After a brief moment, a random person gets an icon over their head and you must MOVE from your spot or you will get hit by her divebomb. She does this three times and then spawns three snakes for you to deal with. You have a brief window till she comes back down and does another set of divebombs. This window is substantially larger than the first set of divebombs.

So, you have memory of this attack because you've seen it in the past. You could even make a macro or use an application to tell you when she is about to come down for the second wave of divebombs. But before all this, the method I used was to simply zoom in and look/listen for the icon to appear above the players head and then move. If your reaction was slow, you would get hit by a divebomb.

This should tell you that there are mechanics in this game that rely on reaction time. Some may argue that there aren't any in Titan because he is scripted but the fight doesn't always proceed as planned. Sometimes you need to improvise...which is what Kettle was getting at. If you memorize his pattern, great: you know how to do the fight without thinking IF everything goes perfectly. What happens when it doesn't? Can you adapt? Will you have the reactions to cover the slack when things go awry?