Word order flexibility

According to Wikipedia, about half of the world's languages take subject–object–verb (SOV) as the primary word order of a sentence, while one third follow the subject–verb–object (SVO) order. English and Chinese belong to the SVO category; e.g., in "She loves him" or "她爱他", if any of the three words or characters is re-positioned, the meaning of the sentence will be altered or be completely lost.

Recently I was reading the very entertaining tale of Phyllis and Aristotle. Legend has it that "Aristotle advised his pupil Alexander to avoid the king's seductive mistress, Phyllis, but was himself captivated by her. She agreed to ride him, on condition that she could play the role of dominatrix." (summarized by Wikipedia) On the Wikipedia page, the Old French verse that told this story ended with Aristotle excusing himself to Alexander, saying

Amour vainc tot, & tot vaincra
tant com li monde durera

with Modern English translation as "Love conquers all, and all shall conquer / As long as the world shall last".

English readers don't need to be fluent in French, much less Old French, to identify the French words corresponding to the English words; e.g. amour "love", vainc "conquers" (think of vanquish), tot "all" (think of total), etc. But what's troubling to me is that the second part of the first line, tot vaincra, is translated as "all shall conquer". The English word conquer is a transitive verb, i.e. it must be followed by an object. It took me a while to realize that "all shall conquer" actually means "(love) shall conquer all". The original author of the verse didn't write "& vaincra tot" simply because the inversion that places vaincra at the end makes it rhyme with the last word of the second line, durera ("last"). But an average English reader having no knowledge of French will have difficulty understanding "all shall conquer". So I edited the Wikipedia page to read "and shall conquer all". A few months later, someone disagreed and changed the translation back, saying it's poetic English.

I took this issue to a language forum and asked for people's opinions. As expected, most forum members agree with me. One even says he initially thought "all shall conquer" meant "all will fight back", which is a totally wrong interpretation. But one member, apparently a native Frenchman, disagreed with me and said the reader should adapt to the text of the author and the translator should respect the style of the author. Others disagreed with him, and my response was that "the adaptation should not go so far as to rendering the 'translated' text incomprehensible in the target language". I have no doubt that his mother tongue influences his appreciation of English speakers' low tolerance of flexible word order. If he were to translate the Old French verse into Chinese (suppose he knows some Chinese), the Chinese verse would probably read "爱征服一切，一切征服", the latter part of which likewise makes no sense to a native Chinese speaker.

In Romance languages such as French or Spanish, the primary word order is also SVO. However, occasionally we see sentences whose constituent is moved to a different position than the SVO rule would stipulate. (E.g. "Ont été reçus Pierre, Paul et Marie", possibly in response to "à Qui a été reçu ?") Native speakers are used to these sentence structures and can understand the meaning based on context and/or the idiomatic nature of such expressions. As far as I know, there is no metric or index in linguistics to measure the word order flexibility of a language. We know that highly inflected languages such as Latin and Russian have fairly flexible word order. But English and Chinese would be quite low on this metric, while various Romance languages are probably in the middle. Sentences such as "That I know", or "那个我知道", of an apparent OSV order, are exceptions, and their OVS variants, i.e. "That know I" and "那个知道我", are completely prohibited or meaningless, even though it may be understood in French in a certain context.