Hi!
maybe French and German too). Problem could be that these standardized forms lead to diacritic characters (e.g. hacek on 'c' & 's'; Чайковский ---> Čajkovskij and Щедрин ---> Ščedrin). Is wikidata able to deal with these?
As a native Russian speaker I can say transliteration like Ščedrin would look very unusual for Russian-speaking person (assuming they have experience at all with non-cyrillic transliterations, which most internet users do). Something like Shchedrin looks more familiar and seems to be much more common. While letters like ч and щ can indeed generate some long combinations which are not very visually appealing, I think it is more common than diacritics, which most people I think would struggle with.
As for Hebrew, there are standard transliteration rules, which look a bit weird since they are not phonetical but rather base on spelling and distinguish some letters that all but lost their phonetical distinction in modern Hebrew (such as kaf and kuf) - but they are frequently used for signs, street names, maps, etc. These rules have been recently updated but old ones still are used from time to time. See more at https://en.wikipedia.org/wiki/Romanization_of_Hebrew