Changing builds in Keynote 6 remains a tedious process involving many mouse clicks. This pair of Applescripts automates that process. There are two because of a weird quirk in UI scripting described in a MacScripter post.
Open a Keynote presentation. For each slide run the two scripts in sequence.
I have them mapped to hotkeys using an Alfred workflow. Using those two hotkeys and the Page Down key (fn-down arrow on a laptop) I can get through a 20-25 slide presentation much faster than mousing through.