The biggest issue with the healer is that what it's good at (in combat healing) is not something that's actually very good. It's much like Monks with their incredible ground movement speed. Yes, that's cool, and yes, they're one of the best at it... but who cares? There are many encounters that can be solved with "this is the best at dealing damage quickly" or "this is the best at killing in the first round" or even "this is the best at being undetectable" which is why classes that specialize in those things, like Barbarians are decent (T4). But in combat healing is generally a waste of actions, while out of combat healing is done far better by other classes (DMM Clerics using Persistant Lesser Mass Vigor, Binders binding Buer, Crusaders with Martial Stance, Dread Necromancers in a party with Tomb Tainted Souls or undead, etc). This is why the Healer is down there with the Monk in T5... what they specialize in just isn't that important.

Eventually in combat healing can be useful when it actually heals more than the damage attacks do... but that's not until Heal becomes available, and Clerics get that too. It's also useful if you do something else along with the heals, but that's what Crusaders do, not what Healers do. Dread Necromancers and Wizards can do it via Necrosis Carnexes, but Healers get nothing like that either.

If you give them the full Vigor line of spells it's helpful, but still not much. What they really need is the ability to do preventative healing so they are ahead of the action game and can be proactive in their protection, as well as easy to get free all day out of combat healing.

Various house rules I've considered for healers have included saying that when a healer heals more hitpoints than the target has, the target gets that many temporary hitpoints that last a number of minutes equal to the level of the spell (allowing the healer to pre heal the party before a big encounter) and letting the healer heal half their healer level + cha mod in hit points as a standard action touch at will. Giving them spells like Recitation would help a lot too.

JaronK