"Help" isn't into dnd. And yes it trivialises the encounter when you can simply healing word as a bonus action with Shadowheart.
Help is however often in tactical RPG and I understand why Larian would want something like this to help the players having a familiar mechanics.
I have would opt to go the middle path and replace help with stabilize (e.g. xcom) another tactical RPG standard that stop player from bleeding out, is more realistic (not everyone is a cleric), and not game breaking.
I would also introduce the throw potion healing mechanics into the tutorial somehow to make them familiar with it.
Stabilise - that is, you use your action to make sure the dying person is not dying, and won't have to make any more death saving throws (they don't regain consiousness, or any hit points, but they are no longer dying, and are 'sfe' until thehy nca be healed, or until they take damage again)... is literally what the D&D 5e rules have for helping a downed ally when you don't have potions or spells. In 5e there is a medicine check involved, so it's possible to fail to stabilise the party member, and I'd happily accept forgoing that check and making stabilise a simple action that just works, in the video game setting, butt other than that, that's actually the ruleset that Larian decided to ignore and not implement.
Healing word doesn't trivialise encounters because it's a limited resource that you're spending, and every spell slot you spend on healing word is one more that you don't have for stronger healing, buffs, or damage-dealing.
