Jesus most certainly had to die for us. While it seems right to think that God is so loving that He would forgive us whether Christ died or not, it's not true. God is definitely loving, and He will do all that is possible to save us (isaiah 5:4), but we cannot misunderstand God's justice. God's kingdom is based on justice, and if God were to forgive us without any penalty being made, He would have no basis for His government. It would also imply that Satan is right in his accusation that God's Law is impossible to be kept.
Jesus did many things while here on earth, but His death was in no way negligible, or unnecessary. Justification in the Bible is described as something done through Jesus' blood. (like in romans 5:9). If we were really saved solely on the basis on God's love, just what would Jesus' blood have to do with justification anyway?
Life is in the blood (lev. 17:11) and without the shedding of blood there is no remission (heb. 9:22). Thus, without the sacrifice of life, there is no forgiveness of sin.
God became human to destroy the devil through His death
[bible]Inasmuch then as the children have partaken of flesh and blood, He Himself likewise shared in the same, that through death He might destroy him who had the power of death, that is, the devil.[/bible] Hebrews 2:14
The reason He came, or appeared, was to sacrifice Himself.
[bible]but now, once at the end of the ages, He has appeared to put away sin by the sacrifice of Himself[/bible] Heb 9:26
[bible]The Lord is slow to anger and great in power, and will not at all acquit the wicked.[/bible] nahum 1:3
[bible]For the wages of sin is death[/bible]ROmans 6:23