The Holy Priest has always been very versatile, but it seems to me that in The Burning Crusade the emphasis has been greatly moved away from tank/single target healing, and more toward raid healing and other utility. This is, of course, only one priest's opinion, and a Shadow Priest at that, so perhaps Matticus will follow this up himself a well. Going forward with this opinion, though, I think there is a lot that supports that thought. Prayer of Mending is bouncing throughout a raid constantly. Circle of Healing has become ridiculously powerful in endgame raiding.
In arenas, healing priests will be specced Discipline, and this healing utility is taken even further. While all healers need to step up their utility and versatility in arenas, Priests are perhaps the pinnacle of that. A Priest that is healing in arenas almost has an element of being an offense-based healer in their utility. There is Pain Suppression for reactive survivability for yourself or your teammates, or Power Infusion to help your healing or your allies' damage. These abilities, depending on how they're used, can be offensive or defensive. Additionally, Mana Burn is an essential spell for a Disc Priest, and it isn't uncommon to see them throw Smites out when they have an opportunity.
Divine Hymn and Guardian Spirit are very in line with the current state of Priests. Divine Hymn goes hand in hand with the AOE healing strength of Priests you see in Prayer of Healing, Circle of Healing, Prayer of Mending, et cetera. It also has that level of added utility we're coming to see in priests, and a utility that has the potential to be used offensively. When one of your allies is struck by an opponent while Divine Hymn is active, the opponent is put to sleep, or stunned, or something of that sort. This is a good defensive maneuver in PvE as well as being a great healing spell, and like spells such as Cyclone, has the potential to be turned around into a pre-emptive offensive maneuver in arenas. Though, obviously, it won't be used exactly the same as Cyclone. It was just an example.
Guardian Spirit is another example of the Priest's utility in their healing. It is described as a castable Cheat Death, and I think it's a pretty straightforward ability. It's a good secondary heal, and its ability to negate a Killing Blow on your ally is a fantastic thing. Great PvE use, and obviously, great PvP use. It doesn't include the damage reduction of Cheat Death in the arena, but buying time by negating that killing blow is great.
Dispersion is the one that bucks this trend of reinforcing current roles. The ability to reduce incoming damage by 90% and regenerate your health by 6% per second is obviously pretty great no matter what part of the game you're playing. It does little, however, to reinforce the Damage/Caster Utility motif of the Shadow Priest. Great ability, but it doesn't move the priest forward in their current role. What it does do is help the Shadow Priest in the arena, where they are incredibly weak if what I know is even remotely accurate. Was this needed? Most certainly! It's a great ability, and that nitpick is really all I have. In the longrun, it isn't a very big deal. There are other things we know from various leaks that do solidify a Shadow Priest's position, so it's not a big deal.
The part that struck me as unusual came in the Q&A portion of this panel. A question regarding the scaling of both Holy and Shadow Priests was asked- whether or not there will be a rebalancing in Wrath of the Lich King. Chilton stated quite clearly that no, there will not be a rebalancing, because both specs are just fine in the raidgame. Shadow Priests, however, will receive arena tools such as Dispersion.
Shadow Priests are highly represented in raids, yes, but it's very clear that their scaling and balancing is completely wrong. Vampiric Touch and Embrace are probably more powerful than they should be, while a Shadow Priest's damage is low enough to be borderline harmful. Scaling one up and one down is not an especially puzzling action (and one they actually seem to be doing, despite Chilton's response) and would solve things quite well. Maybe things will turn out well in the end since what we know does not reflect Chilton's answer, but an 'it's fine' is disappointing regardless of what information is out there. Representation is high, sure, but that certainly does not mean the balance and scaling is at an acceptable point.