First of all, "church teachings" are not just some obscure popified dictation that's occurred in some remote room or remote portion of history. "Church teachings" are either circulated into the mainstream of the church by its leaders & hiearchy, or they are not. (And if they are not, then it's not just a "membership" issue of failing to follow that you try to pass it off on )
I would surmise that any doctrines in need of being "dusted off" due to no air circulation are really no vital teachings at all. So "clarity" isn't the only issue. Actuality of circulation by Catholic bishops, priests, teachers, authors, monks, and other hiarchical leaders also needs to be evident.
So, let's break these down to see if it's a non-sequitor.
So, you're telling me, then, that if I selected the half-dozen closest Catholic schools to where I live, that if I investigated the school curricula, I would find all of these things:
...teachings of the worship of Mary?
...teaching of prayer to deceased people?
...active veneration of holy relics?
Or if I was to review the Catholic church curricula & sermons for the past year of six Catholic churches closest to where I live, I would find evidence of:
...live, active teachings to married women NOT to use birth control?
...20th century Mary European revelations?
I'm not going to argue that the Church has done a great job being forceful and clear with its teachings - I don't think it has. However, your post was "If there's no diversity of Catholic doctrines in the church" - I was just demonstrating no diversity of doctrines in the Church. There isn't, regardless of how much we fail in following the doctrines.
So, you're telling me, then, that if I selected the half-dozen closest Catholic schools to where I live, that if I investigated the school curricula, I would find all of these things:
...teachings of the worship of Mary?
I can't imagine you'll find anyone teaching the worship of Mary, since that isn't a teaching of the Church.
...teaching of prayer to deceased people?
Deceased people? No way! To people that have fallen alseep in Christ, and are fully alive in Him? Then, definitely, I pray to a variety of Saints every day, asking them to keep me in their prayers to God.
...active veneration of holy relics?
You should find veneration of Relics, since things which had touched St. Paul brought Miracles, wrought through the Hand of God. Acts 19:12.
Or if I was to review the Catholic church curricula & sermons for the past year of six Catholic churches closest to where I live, I would find evidence of:
...live, active teachings to married women NOT to use birth control?
I would hope so - Homilies if is germaine to the Scripture of the Liturgy, otherwise in the flyers or groups meeting at the Church. Although if your Priest doesn't think it is a problem within his flock, then maybe not.
...20th century Mary European revelations?
I'm sorry - I don't follow. You'll have to be more specific.