I didn't see it listed in the feature list, but what are the chances of tracking effective healing or overhealing? If I'm not mistaken, it's unfortunately non-trivial. Since you don't get current health reported in the combat log you need to track damage and incoming heals on a per-person basis, and then attribute the healing appropriately.
Any chances of that in the future? I would love you forever. =) It's difficult to compare heals between my scoundrel and our guild's sage since at least in MOX parser it counts every bit of healing from the sage's aoe even if everyone is topped off.
We've already got a plan in place to track overheals and blowthrough heals along with actual heals. It still won't be exact but it will be a lot more accurate than it is now. The basic approach will be to track incoming damage on each combatant and use that to track how much of a heal was actual heal, how much was a blowthrough (actual heal + extra heal that was needed) and how much is overheal (no actual heal, just overheal). Where it won't be exact is when a players max health changes due to buffs and such during an encounter, but it's the most accurate way we can think of at the moment.