Dear Matthew,
The correct, precise words spoken by Our Lady were published in 1921, by Fr. Formigao, the Bishop of Leiria's investigator of the apparitions. In the late 1940's, the prayer changed in the English translation from what were Our Lady's words in 1917. It is similar to the ICEL translation of "pro multis" to "for all". The lack of precision creates ambiguity.
So what? It invalidates the prayer? You bring up "pro multis" which is part of the WORDS OF CONSECRATION -- if you don't have a Consecration, you don't have a Holy Sacrifice, you don't have a Mass.
We're talking about a prayer.
You complain about lack of precision and "ambiguity"? WHO CARES! Are you suggesting Trads will lose belief in purgatory? Guess what, it didn't happen, 80 years later. All the stuff we complain about in the Novus Ordo (downplaying Sacrificial aspect of Mass, suppressing Purgatory, devotion to Our Lady, etc.) DID result in changed beliefs. So while in the case of the Novus Ordo we have 50 years of proof to bolster our point -- in this case, we have even more time (almost 100 years) of proof that goes AGAINST your point (ambiguity, danger, etc.)
I'll repeat my opinion on the issue: it's NOT WORTH all the splits, bad blood, sins, etc. that would result if some Trads tried to impose this NEW translation on other Trads. Some would rally under "Tradition! It was good enough for my dad and granddad, it's good enough for me!" and others would rally under "Purity! It's what our Lady asked for. It's better. That's good enough for me!"
Both sides have a point, both sides fighting to the death to convince the other. Splits, feuds, and strife ensues. And the devil laughs all the way to the bank.
And for what? So Trads can be taught in THIS PARTICULAR PRAYER that Purgatory exists? Guess what? Belief in Purgatory is NOT A PROBLEM among any Trad circles I've ever seen or heard of.
Anyhow, if this prayer isn't the best translation of the original Portuguese, I'm sure Our Lady understands. Would she want us to go on a quixotic quest to impose a new translation on the Catholic world after 75 years? I doubt it. The "normal" translation is a fait accompli, a done deed.
How many sins, how many splits, how many broken social connections is this new translation worth? I'd say less than 3. But there would be hundreds, if not thousands. NOT WORTH IT in my opinion.
How many people will refuse to say the Rosary with other Catholics due to this issue? I'd say this attempt to rock the boat is not a good thing.