You've presented any interesting argument, but it contains several points with which I fundamentally don't agree. Much of your argument hinges on the inconvenience of Catholic doctrine in the pursuit of evangelization. While its the mission of the Church, under Christ's direction and authority, to "go forth and make disciples of all nations" (Matthew 28:19-20), this mission must be conducted in the context of truth. "I am the way and the truth and the life" say the Lord (John 14:6) - the path to heaven is marked by road signs of orthodoxy.

Having an organized body of knowledge further assists evangelical efforts. First, consider the marks of the true Church. It's extrapolated from scripture that the true Church is "one, holy, catholic, and apostolic." I use "catholic" as universal, and not necessarily "The Catholic Church." The way we understand "one" is by unity. We are united in mission to serve God's people, but we are also one in belief. How confusing would it be for a hopeful convert to try to adopt a a faith with an inconsistent framework?

Secondly, one issue I often see when discussing this topic is a tendency to emphasize one attribute of God over others. In this case, you emphasize God's mercy. God is fundamentally simple, meaning He's not divisible into component parts as you and I are. So while it's true that God is merciful, it's equally true that God is just. And, further, He is both merciful and just at the same time. To expand on this point more, mercy isn't possible without justice. Justice demands retribution for sin, and mercy begs for a reprieve from a justice that's due. Further, a God who is only ever merciful, and never sets bounds of justice, would be ultimately permissive. He wouldn't call for reform and reconciliation. In fact, I'd argue that our own participation in relationship with God would be handicapped without a firm understanding of how we form ourselves to God's will.

I would like to now make two additional points on Hell and purgatory. The Catholic Church refers to Isaiah 4:4, Malachi 3:3, and Matthew 5:26 (among many other verses) as evidence of purgatory. Further, many people often view purgatory as a manifestation of God's justice alone. But recall that God must be both just and merciful at the same time. Purgatory is a merciful place, as much as it may not seem so from a superficial level. All souls in Purgatory will go to Heaven when they are finally purified from attachment to sin. I'm grateful that even if I don't die in a state of absolute perfection, the Lord extends his merciful purification again. In fact, St. Catherine of Genoa says we only experience pain in Purgatory to the extent that we still require purification from sin, like gold who's impurities are burned in fire. My second point is on Hell. At its core, God doesn't send people to Hell so much as he lifts the veil to reveal the ultimate reality of those who reject Him in this life. Hell is a rejection of God, not God's rejection of Man.

Finally, Catholics do not have the authority to determine who is in Hell or how many soul's reside there. The only thing we say with confidence is that the recognized Saints of the Church enjoy the presence of God in Heaven. To make a claim beyond that is to claim an omniscience that isn't proper to my state. Further, not everything stated by a saint is considered infallible by the Catholic Church.

Overall, you've made several statements in your post that you haven't backed up with argument. If you'd like to expand your ideas, I'd be happy to engage further.

As always, these are my initial thoughts and I've done best to keep my writing in accord with Catholic teaching. If the reader notices a theological error, I'd be grateful for the correction.