Able to create unlimited excerpt-macros in a page.

And, like other users have suggested, you should be able to create more than one excerpt-macro in a page. Save it with a unique id (related to the containing page) and then make reference to any/all of them from excerpt-insert-macros anywhere.

One of the points of confluence is to allow users to feel at ease when accessing data. And to make the data easily available. Hence you should be able to create as many excerpt-macros in the same page with different content just in the same way as we-humans can make many excerpts from any book/movie-script in the tangible-world.