I understand that the Saints can help make our prayers more efficacious as more people and especially those that are righteous are praying or interceding on our behalf, but the arguments used to justify intercessory prayers can undermine the power and importance of personal prayer.
Would a merciful God, truly ignore the prayer of reckless sinner or someone that does not fully understand the gospel and is trying to find their way? There are many testimonies of people who get down on their luck but completely change their lives by simply praying to God out of desperation. These are cases in which God leaves the 99 to pursue the 1 lost soul. I suspect, God is more open to those of us who are earnest and unintentionally ignorant, as opposed to those that are more knowledgeable.
The Bible makes clear that the prayer of a righteous man has great power and that God turns away from the unrighteous - but why would a saint be willing to offer prayers on our behalf if we are living in an unrighteous and unrepentant state? If God chooses not to hear my prayer because of my choices, why would a saint be willing to intercede on my behalf? Wouldn't this imply that the saint is more merciful than our creator? Isn't it conceivable that the saints would refuse to intercede eventually?
As I think about this while typing it out, I suspect the saints have a better understanding of God's judgement, so their willingness to intercede is an act enabled by God. Additionally, if God refuses to hear our prayers and assuming the saints choose not to intercede, it will lead us to a state of despair and brokenness with the intent to reconcile us back to God.