If God thought of us as you do, as 'dust," Jesus would have never come to dwell among us---to be one with us.  The gospels all tell us that Jesus loves and saves us in spite of our sins.

This theology of yours is a sad mix of Gnosticism and Jansenism.  

Jesus tells us "I came that they might have life and have it to the full" [John 10:10].  
As I place ashes on the foreheads of Catholics [and any other Christian who comes on Ash Wednesday], I will state 'Turn away from sin and believe in the Gospel' [Gos pel-----the Good News from God.