*sigh* Alright, here we go.
When one is in a location at any given time, two things occur. One is perception, which is picking up your surroundings with your five senses, and the other is processing, which is your brain making sense of the information in the aforementioned concept. When you move, or something in the vicinity of your senses' range changes location, your senses pick up this change, and your brain processes it. This is what reaction speed is. It is essentially how fast your senses pick up information, and how fast your brain processes this information.
When you travel, your perception of where things are changes. If you're running towards a tree, you perceive the tree as coming closer and closer, and your brain processes this perception so you understand. If your senses are not acute, or fast, enough to pick up the changes around you as movement is done, your brain cannot process these changes. After all, how can your brain process information it was never given? What this means is that at a certain speed, your senses become incapable of perceiving these changes. This applies to you moving(if you're in a car that is moving too fast, all you'd see is a blur) or another object moving(when a bullet is fired, you can't actually see the bullet traveling through the air at real time). Why do you think C noted the Raikage's armor also enhances his reflexes? Because if his senses cannot perceive the world around him as he blitzes around, he will be blinded. The same thing happened to Kiba. He said that when he and Akamaru spin in Twin-Headed Wolf form, the movement is so fast they cannot keep up with it using their eyes, resulting in them being unable to see.
The same applies for teleporting, whether it be yourself or something else. It applies a hundred times more because teleporting is on an entirely different level above simple movement. The thing about movement speed is there is a passage of time, as speed is distance over time. Meaning, there is a window of time where you can react to the changes. Teleporting, true teleporting(FTG, Ameno, not warping like Kamui), has no passage of time. Between point A and B is zero seconds. The very same millisecond that you are in point A is the very same millisecond that you are in point B. Meaning, your senses have to be fast enough to pick up two separate positions and everything that corresponds, simultaneously within the same millisecond. Any slower, and when you arrive to location B, you'd still have the collected and processed information of location A. At which point, you'd have to pause and take in the new information from location B and let it process. Sasuke has never suffered from that. There has never been an instance where Sasuke used Ameno and was left needing to look around.
Even if Sasuke already has a mental idea of where he'll end up and when he'll end up there and what it will look like, he still needs to be physically capable of making this perception and processing in time. This is why if someone says "I'm going to shoot that spot on that target in exactly five seconds and it will get there in one second" and you visualize the bullet moving through the air, you still can't actually see the bullet as it travels.
