This is a heartbreaker of an omission. I've been copying text formatting with an Eyedropper for as long as I remember. Quark? Pagemaker? I think so. Creating multiple text styles for every document seems like a mess, and my first attempts to do so -- to format an imported PDF -- did not yield consistent results. In InDesign I only go to the trouble of setting up character and paragraph styles if I'm working on a very long document, or a periodical... and sometimes not even then. A heartbreaker. PS: I remember being almost giddy a couple years ago when I learned that in InDesign you could "load" the Eyedropper with a text style and then go through your document highlighting text with the Eyedropper to apply that style.
Being able to specify leading (line spacing) in multiple ways is convenient. I think Quark Xpress allowed leading specifications such as +2, +12, -1, etc. That was nice. Allowing percentages to be entered could also be handy: 100%, 110%, etc. Many programs permit percentages in certain situations (such as setting the amount of "auto" leading), but why not make it a standard option in the Character and Paragraph setting boxes?