Writing seems nmch less important than reading. Some will write reports in English but few need English to write letters. Speaking is the least needed. Only a small fraction of students want to talk to English-speaking visitors and to attend senfinars, which usually require speaking ability. None of them will give lectures in English.
    Based on these surveys,I think the main attention of teaching English should be paid to reading comprehension. Report writing and letter writing should be taught especially to those who would most likely write report or letters later in their career.