If God has all power, why do we need a Savior?

I've heard people question why the Savior had to die. They reason that if God has all power, then he could just bring us back into His presence. 

Envision that happening. Can you see yourself happily being in God's presence as you are now? I can't. A prophet in The Book of Mormon explains what would really happen to us:
"the demands of divine justice do awaken his immortal soul to a lively sense of his own guilt, which doth cause him to shrink from the presence of the Lord" Mosiah 2:38

I've heard of a mall that was having trouble with gangs frightening away their customers. They asked a professional for help. His solution -- play classical music. It worked! Why? Evil is not comfortable around what is beautiful and good. Knowing this, we fill our streets with light, because we know that violence and crime thrive in darkness.
 If people who have made many bad choices are not comfortable around other people who have chosen to be loving, then how would they feel standing in front of a righteous God? How would any of us imperfect beings feel in the presence of a perfect being?

Wouldn't heaven be a hellish torment if you were not the sort of person who felt comfortable there? Would it be a heaven, a place of peace and rest, if those people who want to destroy and harm were there?

Some say that God will make us good, clean, and pure after we die, so we will be happy to live with Him in heaven. This view implies that you can do whatever you want here, and God will give you some small punishment, maybe, and then He will, somehow, make you into a noble person who will sing His praises in heaven forever.

Would God really do this? Would he seize control of our lives and force us to become who He wants us to be? Even if it is into something good, no one likes be be "made over" into what another person thinks they should be, so why would we think that we would appreciate being "made over" after this life?

Would it be just to control other people? Would God use force and treat us as if were were mere dolls to "dress" in the qualities He thinks would be best for us? Would God deprive us of the opportunity to grow? Could God impart courage to us without allowing us to struggle, or compassion without allowing us to suffer?

Would it be just to disregard the consequences of our actions? Could we grow and develop those Godlike qualities, such as love and patience, if we did not experience the consequences of our actions?

Would it be just to give moral laws, then reward equally those who keep those laws and those who break them? Isn't the real reward the natural consequence of living those laws? Would it be just to extend mercy to someone who refuses to try and do better?

Could you trust or have faith, in a God who does not live by law and is not just? Would God still be God if He did not live by eternal law and principles? A prophet in the Book of Mormon explains that if justice was disregarded, then "God would cease to be God." (Alma 42:13). So how can God be a just God, a dependable, righteous being, and still be merciful? How can God uphold the laws which order the universe, but also help us grow so we can return to Him?

Obviously, justice isn't going to cut it. We all make lots of mistakes and some of them even willfully. We don't deserve, nor would we feel comfortable, living with God. I want to return and live with my Heavenly Father, but I simply can't do it on my own no matter what I do, or how hard, or how long I try.

This is where a Savior comes in. It would not be just if mercy robbed justice, and God must be just. The Savior came to pay our debts, to suffer our consequences, and so holding our "notes", He has the right to offer mercy to us if we will repent and agree to change and try our best to do better. Since we have asked for help, committed to the "make-over", and are trying to follow the advice the Savior gives us, our Savior can now help us progress, change, and become more like him. He can eventually purify us. He can help us reach our potential as children of God. He can help us return to our heavenly home and be happy there. These words say it all:
15 And now, the plan of mercy could not be brought about except an atonement should be made; therefore God himself atoneth for the sins of the world, to bring about the plan of mercy, to appease the demands of justice, that God might be a perfect, just God, and a merciful God also. (Alma 42 in the Book of Mormon)

Atonement of Jesus Christ

More About God

My other posts on the Atonement

https://www.lds.org/bible-videos/videos/for-god-so-loved-the-world?lang=eng&_r=1

great video
Handel's Messiah: Debtor's Prison