A) The Spriest team at Blizzard don't actually play the class
B) There ISN'T a Spriest team at Blizzard
C) The Spreist team at Blizzard play the class and care but are wimps and give in to higher authority/other class leaders.
I mean, even moderate raiders get screwed as so many guilds min-max. ( I know, I have heard the whole "If you aren't in the top 100 guilds in the world not bringing a shadow priest cause of dps is foolish") Screw that. GM's and raid leaders who have to deal with 9-24 other raiders griping when a they hit the wall aren't going to risk having an spriest in the raid when an extra Warlock/Mage/Rogue/Hunter are sitting in the wings with equal gear.
If Blizzard realized they are screwing players like me who have 5 or more years into a class out of raid spots or gear drops (why give the spriest the trinket/tier/etc over the other caster) maybe they would balance classes better.
Oh....no, I have had enough. I've got a Warlock in the wings and a pally for tanking....