Let me relate a little memory from CoH that I'm sure others here will share with me. There was one ( I think it was unique in this?) heal ability in CoH that could miss. This was because it was designed as an offensive ability (even though I don't think it did damage) that targeted an enemy, and if that debuff failed to land the heal wouldn't fire off at all. Darkness, I'm looking at you. This could result in those tense moments where teammates were injured, lives were at risk, it was the support's moment to shine........and then sad trombone noises played and a major feature of your character just fails to work. Nothing felt worse than a failed heal.
I know I read that as a matter of design, CoT abilities will only miss if enemies have improved defenses and/or our characters are hampered. I'm just really hoping that none of the healing abilities are going to be based off a to-hit check. At least not support abilities that heal others, where the main point of the ability is healing. Especially when it is the only heal in a support set. These all combined to make it feel much more impactful compared to missing other abilities.
If I remember right, the rez in darkness also needed to target an enemy but I don't think it could miss. Which made the decision for the heal to miss all the more baffling.