In no way is it even similar. You need a target taking spike damage to even begin to do reasonable aoe healing with this glyph. It only heals for 10% of the effective healing. Unless you have a severely under geared tank, then you rarely have anyone with a health deficit of greater than 5k for long enough for a holy light to even be cast.

It is very situationally useful, and does not even begin to reach the aoe healing capabilities of CoH/WG/Chain heal on the majority of fights. If it wasn't OP at 5yds, then it wont be too bad at 8.

If you want to talk about OP healing, we should talk about judgment of light and blood aura. On consistent moderate damage AoE fights these abilities make up a significant portion of effective healing. A ret pally's JoL does so much healing that I would never raid without one. If blizzard ever made a holy paladin's judgement of light more effective than one from a ret paladin, the one who got to judge it on the boss every fight would always top the effective healing meters on any fight with raid damage.