I don't know how the love of God relates to your statement "he makes special allowances for Muhammad but that only detracts from the integrity of the text". But every sin for everyone can be completely washed away after a person duly turns to his Lord in sincere repentance:
Say, "O My servants who have transgressed against your souls! Despair not of the grace of God, for God forgives sins, all of them, for He is much forgiving, most merciful." (39:53)Another ayah says:
My mercy has encompassed everything. (7:156)You can imagine that in Islam, God's mercy with his servants is even more than our own mothers. I really can't grasp your point of trying to deny an attribute of God in Islam.
Please, let`s do discuss the verses that incite to murder...