First and foremost looking at your 8min 10N M Meg wipe you are within a few % of the other healers so don't beat yourself up with respect to your other healers.
As a healer, things you can do to improve include the following constructive list:
1. Living Steel Belt Buckle
2. Change glyph of Rejuvenation for anything else, in said 8 min attempt you cast 0 Nourishes which is an example of an unused glyph, strong recommendations include Glyph of Regrowth (100% crit means reliable!)
3. Do use your tier 2 talent more often as it was used twice in an 8 min fight (anywhere from 7-9 uses in such a long fight would have been more acceptable)
4. Do change your tier 4 talent to either Soul of the Forest (not necessarily easily to master) or Incarnation: Tree of Life (can be used as a mana CD spamming LB's over the raid and using Regrowth on Omen of Clarity procs or as an HPS CD spam whatever you normally spam)
5. Do use your tier 6 talent more often, you used it twice in said attempt (where you can probably fit one in almost every rampage) out of 5-6 possible times. Or if micro managing that talent is bothersome, Heart of the Wild is a respectable tier 6 talent to heal with.
Min / Max comments:
1. Skinning Profession for a profession that provides Int
2. Power Torrent weapon enchant should preferred given the ease of access to Sha crystals this far into the expansion
3. More aggressive usage of defensive CDs (Barkskin has a 45 second CD) which can be saved for every rampage and your symbiosis CD for those special moments.
Have fun!
Sephinia, US -Illidan