I find Lifebloom to be quite effective as a raid healing tool. Even if people are overwriting your HoTs, the incredible speed at which these can be laid out means that most of them will actually pan out for the full healing. It really eases the burden on the other healers. I typically get a whole lot of healing done just spamming Lifebloom on people for Solarian. It also helps to toss one on the missle target too. This certainly isn't going to keep them from dying if your main missle healers are slow, but often times, you'll find that they end up switching to her new target before her old one gets topped off. Lifebloom handles this nicely.
Here's a recent WWS as an example:
Wow Web Stats
EDIT: Abella is my druid.