I like him. This is what the creep Defiler aspires to be.
The slower pace of Warhammer fights makes the healer role more manageable. Unless a squishy aggroes a keep lord, no one drops in three hits. Contrast this with City of Heroes, where I often need to start the heal animation before damage arrived. Nothing will save a non-tank with six enemies on him, but healing is not massive bursts of green against massive bursts of red.
Instead, Warhammer uses many heal-over-time (HoT) spells. With steady incoming damage rather than big spikes, this works perfectly. I got my first big heal at level 8, and I am not in the habit of using it yet. I like the warband screen that shows me hit points as percentages: if you drop below 90%, you get the insta-cast HoT; if you drop below 65%, I stack on the HoT with an induction timer; if you drop below 50%, you also get that big burst heal. Unfortunately, it is slow-casting, and dropping below 50% with two HoTs on you probably means that you have six Ironbreakers hacking at you. Sorry, but level 10 gives me a rez!
Survivability is very good. In RvR, I can stand more or less indefinitely against one target. My Engineer has learned that she will lose one-on-one against a Shaman. Shamans outlast tanks. I recall only one fight that came down to that; we mostly keep going until someone else arrives to tip the balance. Healer survivability may be too high — those are nice HoTs, although large damage spikes will beat them. Hero-class enemies, for example, kill me in passing.
My worst survivability is in large public quests. Say you are in the first stage, in a warband with more than a dozen people, scattered around and beating on the 100 enemies you need to advance. They will aggro at least two dozen enemies, by proximity if nothing else. No one is tanking at least a quarter of that. Healing draws aggro, and there is lots of ranged aggro to be had. Did I mention that nothing will save you once you get focus-fire from a half-dozen enemies? I like guild groups.
Shaman damage is nice, primarily single-target damage-over-time. My main attack in RvR is an instant-cast DoT with 0 cooldown; it goes on every target I see, and that builds up my healing power. It is backed by a second instant-cast health drain-over-time, which sadly has a much longer cooldown time; I can direct the health gain to someone other than myself. There is the standard single-target bolt with a casting time, which I use mostly for pulling while soloing. And then there is the big damage spell, a channeled single-target DoT that does a lot of damage. Sure it drains your action points and keeps you from doing anything else, but it is the spell that makes your target run away or lie down. You get used to seeing little green men with little green death rays around the Gates of Ekrund. Toss a half-dozen HoTs on your allies to charge up, then zap. (And toss a half-dozen DoTs on your enemies to charge your healing.)
I do not devote much effort to that healing/damage balance. It is a nice little bonus, but I do not rely on it or actively work around it. I use it if it fills up, and I prefer to use it with insta-cast spells that get increased effectiveness rather than slow spells that get faster casting (big DoTs and HoTs). Maybe I should find or make an add-on that shouts HEAL/KILL SOMETHING when I get to 5.
I mentioned that the Engineer has few flashy effects to attract attention. The Shaman is much the same unless I use the glowing green death ray. If I toss a DoT or HoT, there is no line that leads back to me. Being short has its advantages in terms of not getting clicked on, or not being visible at all behind the massive wall of Black Orcs and bouncing squigs. And then there are the scenarios where an Ironbreaker and a White Lion devote themselves to attacking me at all costs.
Oh, and there are buffs. The resistance buff is what I asked for: instant-cast, whole-group, and it lasts an hour with negligible cooldown. I can toss it excessively in case someone died or had it dispelled. It does have a flashy effect, like a green shockwave. The damage buff is more of an in-combat thing: you have ten seconds to use it on one attack, although everyone in the group gets the buff. More green glowy effects! And I have an action point drain that I don’t use much yet.
The class flavor is good, very green. Spell names are in that vulgar orcish argot, but they are fun. I have mentioned the several glowing green effects. The goblin squeaks and whines. He is a petulant little pagan who keeps people alive while zapping his enemies. He has no armor, but that is what orcs are for.
Bonus flavor: the Engineer gets a “tool belt” of vengeance and whatnot. The Shaman item of the same series is called a “bitskeepa.” It keeps his bits.