You've just gotten a new piece of gear and you want to see what swapping it in will do for your gameplay. So you head to the nearest major city and find a training dummy to hit while you keep an eye on how you're performing. This seems like a good plan until you realize that training dummies really only help measure your DPS -- there's no easy way for a tank or healer to gauge how new gear helps them without jumping into a raid or dungeon and seeing how it performs. While that certainly works, it means those classes don't have an easy measuring stick.
This is exactly why Healer CDs has argued that healers need their own healing dummy -- and on Twitter, Celestalon has chimed in saying he sees the value in the idea... but isn't sure if it will be included in Warlords. We'll just keep our fingers crossed.