The newest Doctor of the Church will be soon announced, and the first one I believe, to significantly predate the classic 8. By at least a century. You can learn about him here.
One of his most famous quotes (it seems to be almost everywhere on the net) is this:
The glory of God is a human being fully alive; and to be alive consists in beholding God.
Do you suppose there’s an optimal number of Doctors? Catholics continue to name them–they all seem to originate in the Eastern Hemisphere. Of all the New World saints, who would you muse is closest to the title from North America, or Latin America? What about East Asia or sub-Saharan Africa? I suppose we will be truly free of the Tridentine clamp put on mission lands when we see doctors from the Philippines, or Brazil, or Canada.
Catholic Sensibility 
I would propose Saint Oscar Arnulfo Romero. His pastoral letters and LONG homilies are incredible. And, in his speech at Louvain less than two weeks before his martyrdom, he ended rephrasing Saint Irenaeus:
“Early Christians use to say GLORIA DEI, VIVENS HOMO (‘the glory of god is the living person’). We could make this more concrete by saying GLORIA DEI, VIVENS PAUPER (‘the glory of God is the living poor person’)”,
[“The Political Dimension of Faith” in ARchbishop Romero, VOICE OF THE VOICELESS (Orbis, 1985)]
The odd thing about this is that St Irenaeus of Lyon was a martyr, and would be the first martyr Doctor. So, liturgically, it will be a curious case to see if/how his office/propers may be changed or not.
“Of all the New World saints, who would you muse is closest to the title from North America, or Latin America? What about East Asia or sub-Saharan Africa?”
Whose teaching therefrom has become a standard reference for you? The question puts the cart before the horse, as it were. The cultus precedes the proclamation.
It’s likely more a swipe at my impression of the weakness of the overall missionary effort in the Tridentine Era. More and more, I think of 1570-1962 as a worse period than the Dark Ages was for the Roman Catholic Church. The emphasis over the last few centuries has been on founders, not teachers.
Is teaching inherently more important than founding as an inspiration for discipleship?
I am not persuaded about your perennial whipping boy; perhaps there’s a case to be made, but I don’t think you’ve come close to really making it – it’s more of a tic than an sustained, deep and broad argument based on history. But we’ve had that discussion before.
There are already some calling for naming Romero a doctor of the church – including Monseñor José Luis Escobar (the archbishop of San Salvador), Cardinal Gregorio Rosa Chávez (of El Salvador), Peruvian Dominican liberation theologian Gustavo Gutiérrez, Fr. Robert Pelton (of Notre Dame, I believe), Archbishop Kalenga (nuncio to El Salvador speaking to CELAM in 2017).