It would be nice to have a dynamic target word count, for the segment and the document, shown in the status bar. It could be shown as an absolute number of words and/or as a percentage compared to the source word count.
Some clients require that the translation be shorter, equal or only slightly longer when compared to the source text word count. We need to be able to know before the file generation, during the translation phase. We cannot indicate a maximum number of words per segment, because the segments are all different lengths.
This solution would be the easiest for translators in similar situations.