Go look at any forums that discuss healers in pvp and the general consensu will be that Holy pallies are OP and Priests are the worst healers at 85 atm on beta. Here's a couple reasons why:
-Disc mobility still sucks and Inner Will is not going to help at all.
-Disc mana regen is terrible (its impossible to stack evangilism to more than 2 or 3)
-Disc does not have dispel protection so our 40k+ shield can dispelled instantly
-Penance does not heal for enough
-Everyone has an interrupt so good luck casting anything but Flash Heal and Flash Heal drains our mana extremely fast
-The one thing that used to make up for this was our ability to do decent damage for a healer, but now every healer can do just as good, if not better thatn priest damage (Holy pally's with Holy Shock and exorcism
I could go on but i think you get the idea.

I did have one thing to mention about Holy. I like Chakra but I don't think its fair that we have to juggle "stances" to do decent healing and, as you put it Zach "if you're not in Chakra, you're doing something wrong". To go along with that, If were in Chakra then Holy Word: Chastise gets changed to something else, but HW:Chastise is a great pvp ability without being changed (a 3 sec stun and small amount of damage). So we get punished pvp wise for being in Chakra but if we're not in Chakra we still get punished.