With regards to mistranslations of verses, it seems to me that you may be confusing different things. You seem to be under the impression that a good translation will enable you to understand all the issues, rulings, conditions, and wisdoms pertaining to a verse. The reality is that even if you knew arabic you would not be able to get all these things by just reading the verse - that's where you need to consult the books of tafsîr which quote other Qur'ânic verses, the teachings and example of the Prophet saws, the understanding of the Sahâba, notes from arabic linguists, etc. to explain the verse. No matter how many ways you translate 'establish salâh', a person will not become knowledgeable about all the issues and rulings pertaining to salâh just by reading that translation.