DK healers feel so bad to play because of Obsidian Shard now. While Obsidian Shard is a great skill now compared to past iterations, it still has some glaring flaws that I hope eventually get changed so that the DK burst heal doesn't feel so limited in use. The great things about the skill are the fact it is a strong burst heal for up to two targets, the damage component can proc burning, giving back resources, and it has a theoretically super long range.
The main issues are target must be an enemy, and the range to hit an enemy is low. The range on the heal is 28 meters from the initial target, which is super amazing, it gives it a theoretical reach of 15m plus 28m from target. However, the issue is that the initial target must be an enemy, and must be within 15 meters. This means if there are no enemies close by, you cannot use your burst heal, an issue other healers do not have. That plus the fact you have to be within 15meters specifically of an enemy means it is really difficult to use your burst heal in some circumstances.
A smaller issue is projectile speed and the fact the heal doesn't go off until the projectile hits. This means that your heal may take longer to hit than a healer like a templar or warden, and while a few tenths of a second may not sound like much, sometimes it is the difference between life and death (like in PVP).
I feel like a solution to these issues is to make Obsidian Shard behave more like other burst heals, in that the initial heal is instant, and you target a player with conal selection like Rushed Ceremony or Twilight Matriarch. Due to its other components, it should also still keep the 15m range (frustrating though it is), and still cause the magma to flow forth from the ally, healing another nearby ally, and also fling the shard forth from the ally to damage a nearby enemy for marginal damage, so that DK healers can still be able to benefit from some class passives even when healing. It is the heal portions that should be instant, the projectile should still have travel time.
TLDR: I think improving Obsidian Shard by making it cast on ally will make DKs less frustrating healers to play as