Stopped using it when Morrowind hit. I swapped to Honor the Dead and I use that morph for PvP exclusively. Healing Springs and Combat Prayer are my heals now since they are cheaper and hit more people. I also keep Ritual of Retribution down and every 15-20s a barrage of Healing Orbs.
BoL has been labeled as a conal heal for a while now, not sure why a trials healer would not know this by this time. Now, technically there is a bug with BoL where the 2nd heal is ignoring the conal requirement but that doesn't really excuse anything.
Trials healers should be relying on stacking healing springs to keep players' health up. BoL is generally an emergency heal but it'd be really difficult to time it properly without the intended target dying before the healer responds. I guess you could rely on it a bit more in normal trials, especially if it's one where you have to be more mobile as opposed to stacking, but even then there's no excuse for not knowing that you have to be facing your target.