I'm pretty sure left clicking the name in the party window works. It does lack solid, visible feedback that it did work, and that you are targeting your chosen ally. Your targeting orb might switch to them, and you will spin to face them and move towards them to cast, and their hit box might be up around them. But those indicators require looking away from the party window and that is kind of the last thing you want to do. Some sort of highlight or indicator in the party window would be nice, like a drop shadow or a bullet point for the active.

It is easier to notice that your abilities are working at higher levels, when adding back a couple of hundred HP to someone with 500 HP it easier to notice that you did that. Still there is confusion most of the time, because you don't know for sure that you are the one that did the heal. They could have healed themselves, got a combat refresh or been healed by someone else. If the stat bars filled up with white for a second if someone else did the repair, and filled up with some other color to indicate you did it that would give extra feedback to the players. But battle is confusing and not sure if any amount of feedback would remove that confusion.

Assist? Some game mechanic from some other game? There are so many ways that you can assist an Ally I don't see how one right click could know what to do. First Aid, Reconstruct, Revitalize, Pep Talk, Healing Injection, Lend Grace, Mud Bath, Rally, Moment of Resolve, and probably plenty more. Even if you made it easy and simple said Use Major Healing ability on Right Click of Party Member name there still be the question of which if you had one Major Heal on both ability bars. If it was automated and controllable, it would require it's own GUI. If it was automated but preset, then people would want use minor then major healing, use major then minor, use the healing that gets closest to getting them full without going over, use all heals until they are full. And that doesn't touch on Armor or Power boosts or evade or protection or accuracy. Or maybe I just misunderstand what this Assist is and what it should do.

I think the best choice is to identify particular issues and offer ideas that might address that issue. Somethings might be too difficult to implement, somethings might be on Citan's todo list already. But feedback can help improve the game, especially if it is detailed and constructive.