I think you're ignoring a few important dialogues in the story:
In Genesis 21 God tells Abraham: "...it is through Isaac that your offspring will be reckoned." (v.12).
This was a continuation of the promise God made that He would give Abraham a son with Sarah, even though it seemed impossible. Abraham had to persevere in faith to believe any of God's promises. When ordering him to sacrifice Isaac in Gen. 22 it is to make certain that Abraham realizes who is in control.
As the two of them went on together, Isaac spoke up and said to his father Abraham, "Father?"
"Yes, my son?" Abraham replied.
"The fire and wood are here," Isaac said, "but where is the lamb for the burnt offering?"
Abraham answered, "God himself will provide the lamb for the burnt offering, my son." And the two of them went on together.
Abraham knew He was doing God's will, that God would provide, but He also knew God was providing on the basis of his
obedience. God was more interested in preserving a faith that would ensure survival, than in a survival that would only lead to death, if you follow my meaning.
"I swear by myself, declares the LORD, that because you have done this and have not withheld your son, your only son, I will surely bless you and make your descendants as numerous as the stars in the sky and as the sand on the seashore. Your descendants will take possession of the cities of their enemies, and through your offspring all nations on earth will be blessed, because you have obeyed me."
Of course, this isn't all there is to it. Listen to what Paul writes centuries later:
Romans 8
31What, then, shall we say in response to this? If God is for us, who can be against us? 32He who did not spare his own Son, but gave him up for us all--how will he not also, along with him, graciously give us all things? 33Who will bring any charge against those whom God has chosen? It is God who justifies.
Your charge is that God should have been less demanding in his expectation of faith. But God just showed what kind of sacrifice we might have to make. God completely justified Abraham's faith - we can't say Abraham sold his soul because the same faith that he had in God is the one that will rescue us from the fire. If we don't believe God can provide salvation, we are lost.
Or to put it more clearly: if God did not ask Abraham to intrude on Isaac's freedom to live, our faith would have been to weak to mean anything. And if God hadn't shown in this way that He has mercy and not death in mind, what little faith we did have would have been in vain.
What you call "intruding", God calls "intervening". He has to intrude on our life if He is to intervene in our death.