Most ancient languages, including most ancient Indo-European languages, like Latin or Ancient Greek, allowed a free order of the words, because there were markers for each syntactic role, like agent, patient, instrument, beneficiary and so on (i.e. the so-called cases).
Nevertheless, at the stage where the old Indo-European languages became attested in writing, they had a very serious defect. Even if the so-called case terminations of the words were originally a small set of post-positions corresponding to the syntactic roles, due to various phonetic evolutions conditioned by the adjacent sounds present in words, the original small set of markers had diverged into a very large set of word terminations with many distinct variants for each syntactic role, the so-called word declensions.
Because remembering such a large set of word terminations became too difficult, most modern European languages have abandoned the old declensions. Some languages use enough prepositions, possibly together with some remnants of the old case terminations, to allow a free order of the words.
English however, depends a lot on the standard order of the words to convey their syntactic roles and it has only limited means of expression for supporting a different word order.
While in the Indo-European languages the too irregular word declensions could not persist, there are other language families with a much more regular structure for the syntactic role markers, while still having enough markers to allow a free word order.
It is weird that the European linguists of the previous centuries considered the regular languages (the so-called agglutinative languages or isolant languages) as "primitive" while considering the "flexionar" classic Indo-European languages as "superior" and "advanced".
In fact even if the flexionar classic Indo-European languages evolved from some older agglutinative language, their irregular declensions were a serious defect and not a sign of progress.
Unfortunately, because the language changes have always been done mostly by the less educated people, without having any kind of grand plan of how to best improve the language, the necessary simplifications of the language have also been frequently accompanied by a loss of expressiveness, like in English.
I am going to lookup what you wrote about the evolution and use of active voice in English - something I always wondered about.
Unfortunately, in English, if you want to make the patient the topic of the sentence you are forced to use the passive voice, because there is no marker for the direct object of a verb, and then the sentence becomes less readable, because in English the passive voice is constructed with auxiliary verbs, so it is more complex than the active voice.
These are defects of the English language, so the recommendation to avoid the passive voice is specific to English and also to a few other modern European languages, which have also lost the features that enable a free order of the words.
In an ideal language, it should be possible to use a standard order of the words to express their syntactic roles without additional words, but there should also exist some optional prepositions or postpositions marking each possible syntactic role, to enable an arbitrary order of the words when desired.
In such a language you could choose freely the topic of a sentence without being constrained because some choices are awkward, like when using the English passive voice.