Even though Merton was Roman Catholic, I do not think his desire was to be enshrined in some cult of "the great saints." Merton appreciated anonymity, and lived it out, in huge chunks of his life, in his Trappist hermitage in the Kentucky woods. This was the cultivation of growth in holiness, done in anonymity, with the result of great influence for God and his Kingdom. I know this, because every day God speaks something through Merton to me.
To be a "saint." "Saint" is a good word. It was never meant to mean something like: "very special and venerated spiritual hero." It comes from the biblical Greek word hagios, which means: "set apart." A "saint" is a Jesus-follower who is set apart for Christ and his Kingdom. The life of a saint is a life fully reserved for utilization by God. The motto of a saint is: "I am your's, Lord. This and every day." And: "Use me, Lord." And "Here I am, Lord. Send me!"
For Merton, set-apartness required simplicity. This means: focus on one thing, on life's most important thing. Simplicity is not the same as "simplistic." "Simplistic" is shallow; "simplicity" runs deep.
A holy, set-apart life is a life of integrity. This is like Isaiah being "undone" and unravelled and dis-integrated for the sake of his re-integration by the hand of God. "Integrity," in metallurgy, is about seamlessness and consistency. A piece of metal that has integrity is the same at every point; a holy life is "set apart for God" at every point and every situation and every part of one's being. This, for me, is what Merton's desire to be a saint is about.
For Merton the challenge was that he was "all mixed up in illusions and attachments." (Ib.) These are impurities that weaken life and threaten one's structural integrity. They indicate areas where one is not given over to God.
What is required is "a complete and holy transparency." A "saint" becomes a person who is less so that Christ can be more. We see Jesus in the life of a saint. God is encountered, not some ego-driven person. Saintly, holy living then looks like this:
"God is greatly to be feared in the assembly of the saints,And to be held in reverence by all those around Him."
- Psalm 89:7
"The saints of the Most High shall receive the kingdom, and possess the kingdom forever, even forever and ever."
- Daniel 7:18
"To all who are in Rome, beloved of God, called to be saints: Grace to you and peace from God our Father and the Lord Jesus Christ."
- Romans 1:7
"Called to be saints." That's you. Desire this.