I am not familiar with the history of Arabic typography, but I sort of assume there was an archaic block form and their current joined form is the result of many centuries of encoding hand writing practice. advanced enough that falling back to a block form is impossible with the side effect of making simple mechanical text formatting also impossible.
As for Chinese derived characters. we currently are able to jam them awkwardly into our alphabet optimized structures(one code per character) but I wonder if a Chinese native encoding would look different. Would it make sense to try and represent the sub-characters present in each Chinese character in the encoding? I suspect not, Chinese works, but it also does not appear amiable to simple mechanical assistance.