"We have a king, young and tall." Perfect English, perfect translation, yet wrong according to you. This sentence is not complex and you are wrong to think that there is one and only one translation possible in English: ALL of these are correct: We have a king who is young and tall. We have a young, tall king. We have a young and tall king. We have a king, young and tall.
Of all these, yours [the third] is the least idiomatic in English.