Look at it this way: Evangelism/Archangel is optional.
They are giving disc. priests a way to do a little damage while they heal, with a bonus to healing to make up for the time/mana spent dpsing.
Ret. paladins have a similar mechanic that encourages them to heal while they dps. It was already determined by the paladin community that taking 2/2 Selfless Healer would certainly not be a DPS increase, so instead we find that taking a different utility talent in it's place is preferable.
So instead of looking at Evangelism/Archangel as a necessity for a raiding disc. priest, maybe start looking at it as a way for a priest to do a little DPS on the side while healing mind-numbingly boring heroics. There are certainly other helpful talents you can take. I'll help you out: http://cata.wowhead.com/talent#bfhzrosbfRMo
Don't really need to look at it that way at all since evan/arch/atone has shown to be an efficiency and hps increase over heal (and there aren't really any better options).
But that might be a way for those still uncomfortable with smite healing to at least ease themselves into using it.
EDIT: made this post before I saw the changes. Waiting with baited breath to find just how much more boring this makes disc :P
As I said on the old wow forums:
The PoH one is a change I'm 110% behind yet adding more healing via grace seems a bit ugh. I'm not sure how these new changes effect the deathmatch between heal and atonement, yet in some ways the grace buff - encourages - using shields on the raid while focusing actual heals on a single target. The grace buff appears to be devaluing a lot of alternative options, outside of heal spamming a single target. Smiting may now *truly* be just for getting arch, which should not be the case.