clerics, i dont know, maybe because they are almost always in demand, or can solo pretty easily (depending on build), or because they tend to be quite difficult to those not used to playing a cleric (ignoring an enemy when your on the front line is generally ok, you might just loose them, maybe another teammate will pick them off, or they will wack the back of your head once then you rape them, ignore an ally due to distractions, and you have a major problem, they will ***** at you, they might die, the party might loose, playing a good cleric that can still participate in battle requires alot of attention, if at least on your HUD)
very few people/parties wouldnt be made better with the addition of a cleric, only exception in my book is a arcane warforged party in D&D
And, added bonus, got to many clerics, they can replace their spells with damage/debuf spells and be quite good damage dealers
and, as always, turn undead (or channeling)
oh, and your allies tend to put priorty defense on you, as long as you dont suck, and they dont suck...
