Why does brain control opposite halves of the body?

This picture shows three diagrams.

The circles show the retina, the lines are optic tracts and curved lines resemble the cortex

The third diagram in the picture shows what may have been the arrangement- the right cortex receives visual signals from right eye. But the images on the nasal side will be seen on the temporal retinas of both eyes, which will be seen as double. So the arrangement is not feasible.

Now we come to the first diagram, this is what actually is-

The nasal fibres (carrying impulses of temporal field of vision) cross over. 

And since right cortex receives impulses from left side, it sends motor impulses also to the left side

Now here is my question-

Why don't the temporal fibres cross?

If that would happen, the same half of brain will control same side of the body! Human anatomy could have been so much simple 

If you get answer to this question-

Plz post it as comments 

Thanking you

Human body-the best creation ever

  Well, this blog is gonna be much of scientific or medical knowledge. But I need to take its help to prove the point.

  Before I write this, I want to say-

"I solely am a medium to convey the following information. The source is a very respected professor at my college. Dr. K. Shyamkishore"

   According to him, the makeup of the human body was predefined and decided. Saying which, he concludes that- "THUS ANYONE WHO UNDERSTANDS ANATOMY, WILL ALWAYS BELIEVE IN GOD". 

  He gives an example-

1) the sternocleidomastoid muscle-

Every muscle is innervated contralaterally, except the sternocleidomastoid (SCM) muscle. For lay people, this is a muscle of the neck. When one side of the body is paralysed (say right sided hemiplagia), then all the right side muscles except right SCM plus the left side SCM get paralysed! Paralysis of left sides SCM causes head to turn towards left, ie towards normal side.

  It would make no sense to have right side hand paralysed and keeping the head rotated to the right! You wouldn't have been able to see what you are doing with the left hand.

   Having a paralysis of right hand muscles and having the head permanently fixed towards the left makes more sense.

2) the fingerprint-

  Every fingerprint on earth is different. Even in the case of identical or monozygotic twins!!! Not only that, any single finger print is unique compared to all the prints in the past and all those in the future. This leads us to think that there's something that connects the past, present and future finger prints...this remarkable task...can only be performed by the almighty.

3) the right cerebral lobe is for imagination.  The pathway for ideas is cosmocortical tract. Cortex is connected directly to cosmos!

 A case Corpus callosum hemisection, is as good as two different people living in one!

  "THUS ANYONE WHO UNDERSTANDS ANATOMY, WILL ALWAYS BELIEVE IN GOD".