Scale Big - By Character works correctly for me, I suggest you repair Keynote by doing the following:
ensure you complete all the tasks and in the order shown:
1 delete all the iWork applications if you have them, not just Keynote by using Appcleaner from Mac Update to do this, its freeware
2 restart the Mac; Apple menu > restart
3 immediately after the start chime, press the shift key until you see the Apple symbol.
let the Mac fully boot up, it will take longer as the OS is repairing the drive
4 when fully booted, go to Applications > Utilities > Disc Utility; click on the boot drive then First Aid tab and click repair disc permissions
5 when complete, restart the Mac normally
6 install Keynote from the Mac App Store
please report back.