Shaman is usually the best choice because of two reasons, in *my* opinionn
Reason #1 is that Shammy wards get "eaten" first, so generally, the shaman is actually the primary healer while the second priest is spot healing and group heals etc.
Reason #2 is that it will shave an entire second off their group ward casts, my old main was a defiler and omg...
...A shammy on TC is like a shammy on crack!!! I would beg, steal, and kill to get TC when my main was a defiler, cuz my healparse.... holy crap did it fly off the charts, lol.
To cast a group ward and a single target ward on someone, it takes 7 seconds, and usually the ward is "eaten up" before you can cast it again, so all you can do is damage reduction by spam warding and during your breaks throw out a debuff or two, if they have time but they probably wont depending on the group and incoming damage
IF you are in a general group setting the shaman can then take that extra free 20% of the time (because they are casting faster) and debuff the shit outta the mob.
If you are in a raid setting the damage overall taken by the group is reduced greatly because the shaman can afford to put out "more" group wards and spam them faster.
For us fast casting illus types.... you would probably be trying to slit your wrists with a dull knife with 7s cast timers, so they definitely appreciate the faster pace. ;)
My logic is Shaman > Cleric > Druid
Give a druid TC and he's going to spend that extra 20% of the time nuking shit anyway

. (which mebbe for the better.... if your in a group setting and shit isnt dying fast enough!)
Give a Cleric TC and they'll be able to heal the tank more, but their overall damage reduction to the group (i.e. you staying alive), isn't as great as a defiler.
But thats just my opinion
