I'm beginning to believe that the Smite glyph isn't really going to be worth it for PvE. It'll be nice while soloing high health mobs, but for a healer, keep this in mind;
A) You lose a glyph slot.
B) Your rotation changes, and as we're not trying to be a DPS here, this might not always optimal. Currently, we ideally Smite five times and then pop Archangel. Sometimes we might end up only having two or three GCDs to spare, and while throwing in a Holy Fire instead of that first Smite should be a slight DPS increase there, you'll have one less stack of Evangelism to use Archangel with. The thing is that your 'optimal rotation' becomes longer, and as a primary healer you might not be always able to get it in there. Especially not since you replace your first Smite with a Holy Fire, which means you don't get Atonement's heal in.
C) For a second, lets just imagine that grabbing the Smite glyph and going HF>SmiteX5>Archangel bumps our DPS by, lets grab an absurd number and say 50% over the SmiteX5>Archangel rotation. Instead of 5K DPS we're doing 7500 DPS. That's pretty cool but
we are still playing a freaking healer. We should focus on keeping folks alive - DPS is what you do in your spare time, and I can guarantee that adding in that Holy Fire will at least once per fight impede your ability to heal.
Also, like I said, I became more interested in trying a Borrowed Time-less build. Result of these two considerations is that I might give
this spec a whirl at 80, with those glyphs. Depending on how stuff looks like in Cataclysm, I might actually sod Inspiration and fill up Veiled Shadows while grabbing Desperate Prayer. I'm feeling radical!