Comment 8 for bug 432879

USC now shows the "Total size" of something you are considering installing, both download size and installed size.

Unfortunately the packaging system isn't yet smart enough to calculate whether there will be enough disk space, because it doesn't know ahead of time which installed files will go on which partitions.

USC still doesn't list dependencies if you want to know that for other reasons. Someone could implement a secondary Info window to display that information.