You should add Heroics into the "Hard-o-meter" and have each seperate one in there. It could scale from Mechanar and Slave Pens to Mana Tombs and Magisters. At the very least you can place Heroic somewhere on the main bar.
Currently One of my Alt's has a small green bar and just before the kara logo it turns red. So it would help greatly in choosing which heroics I can heal in and which I will become a liability in.
You could even add another bar above the raid one to keep it uncluttered. This will allow people gearing straight from greens to SWP to know where and what they can compete and complete.