There was great consternation when the translation words of institution were changed from "for all" to "for the many." Preceding from the fact that the Latin was always "pro multis", there is a great theological issue at hand.
Can the will of God be thwarted?
In today's gospel we hear "it is not the will of your heavenly Father that one of these little ones be lost.” In 1 Timothy 2 we read, "This is good and pleasing to God our savior,who wills everyone to be saved and to come to knowledge of the truth."
In the history of Christianity there have been those who have argued, based on this text, that in the end the will of God must triumph and everyone will ultimately end up in heaven. The Catholic Church teaches that while we should hope and pray for all to be saved, it would be wrong to say that it must be.
On the surface this may seem harsh, but in reality it is grounded in Love. Because the relationship God wants with us is one of mutual love (God loved us first, and we should love him in return), it must be freely given.
To say that because God wills the salvation of all, all must go to heaven would take away our freedom. God loves every person he created, and wills that all be saved, but because God loves us so, we have the ultimate freedom. God has put our freedom above his will. God does not will that any person be lost, but the choice is ours.
We hope all will be saved, and the church has yet to declare anyone to be in hell, unlike canonization where we declare them to be in heaven. But the free choice to accept or reject God's love is ours, and we make the choice not once but every day in the hundreds of little choices that we make.