Let's imagine for a few minutes that you are a sculpture artist.
In front of you is a block of clay. What will you make of it?
There is the option of diving in with your hands without any intention whatsoever. Or you may have an intention, an idea for what you want to make - and have some blue print in your mind of what you'd like to end result to be.
Now you start working on the block. As you perceive the form progressing, you adjust your forming actions - it is an interactive process between you and the block of clay. You 'in-form' the block of clay, and the block of clay 'informs' you by reflecting back its current shape.
Step by step you shape the block into the form you like.
Now, replace the clay with you. Let's say, before you were born, you were given a block of clay - and that block would become you in this life: a personality and a physical body. An idea may come to mind of what you'd like to experience in this life, and what form (personality and a physical body) would enable that experience. This idea would come out of you - you as the soul being who wants to experience life in a certain way. Being the unique soul you are - your formation process of the block of clay is inspired by everything you know and have experienced throughout your existence.
Two restriction are then applied to your sculpture creative process. Before you are born, you can only design the blue print - you can't touch the actual block yet. After you are born, you must forget the blue print entirely and start the forming process based on the interactive process we described earlier. You dive in with your hands and as you see the shape of your clay block change, you decide what to do next.
If you would be the creator of life, why would you set the rules this way?
Ask yourself, what makes a movie interesting? Don't tell me the ending! What makes a game interesting? I don't know which way it will go!
If you are the creator of life, and you want to control the outcome, you'd set the rules differently. You would tell the sculptor what to do and how to do it. But if you want to be surprised by the outcome, curious about what the sculptor may create that you'd never have thought of, then you'd say nothing. Your free will is at the heart of the decision to set the rules this way.
What would be the meaning of billions of beings, if all would be controlled by one? You'd have billions of mostly the same. Setting free the creativity in all billions of beings creates the spectacle of unlimited potential and diversity.
When you were given the block of clay before you were born, you did have an intention and blue print. In this case you are one of the billions of unique beings planning your sculpture. If this is true, then once born, you are your personality in your physical body, designed to live a certain experience. Why would you make your personality forget the plan you yourself made at your soul level?
Think of the weight difference between a decision you need to make while knowing all the information and outcome versus not knowing the outcome and consequences of the decision. The weight on the decision in an unknown situation is much higher. The experience can become far more intense this way. It will let you search the exact balance through a process of exploring opposites based on experience - not just an idea or blue print.
Also the blue print is not the block. The world is a dynamics place and not all interactions are known (that would restrict free will again). The question was once asked if war was intended and foreseen by the 'gods. The answer was: no. The human hands make tool development possible. Tools could be use to construct and destruct. How humans use what is available is up to their free will. War was apparently a possibility in the infinite ocean of potential and never expected or intended. Being human is a learning curve in itself. Making the sculpture based on the blue print is also a training process.
The third reason to forget is that a blank sheet opens possibilities. We sometimes notice that as people get older, it is more difficult to learn something new. As you learn in life, pathways get set physically, emotionally and mentally. You start preferring these routes and it can becomes increasingly difficult to unlearn and learn something new. Starting life with a blank sheet lets you create original new pathways. It breaks the cycle. In hypnosis, when people experience past lives - it is often mentioned that life lessons needed multiple lives to be completed. It may also be the reason for the change in length of lives. According to some sources, humans used to live much longer. Lifespan become shorter as we had more difficulty to stay 'open', got stuck in patterns that required a reset to avoid complete stagnation.
From this point of view, the weight, unknowingness and openness enrich the human experience. How much of a thriller it becomes is still for a significant part up to your free choice - yet some markers were set to show you the way. The nature of your chosen physical body, the tendencies and preferences of your personality, the family you are born into, the environment you live in, the people you meet, the talents you develop, the things that attract you - this is how you remind yourself of the sketches of the blue print. When those elements have enables you to experience and learn what you intended, new doors open. Until then, the movie doesn't end and the scenes seem similar and repetitive.