I believe that the current system is limited and wrong. I believe that the discipline branch should not be an addition to the holy branch. It should be independent or complement both holy and shadow branches.
I'm inclined to believe that there should be combat talents in the discipline branch. After all, a priest can use melee weapons, but right now it's just a slot for an item with parameters. The discipline branch already has a talent for strengthening wands, then why not give a talent for strengthening melee weapons, as it was in one of the old versions. There, the Improved Inner Fire gave an attack bonus. At least this can be returned. But it's better to redo the branch more so that it clearly reflects the fighting style, not only of hand-to-hand combat, but also magical additions.
Examples:
Improved Inner Fire - instead of a percentage increase in Inner Fire, give new parameters, for example, a bonus to attack power.
Mental Strength is an interesting parameter, but I don't think it's what a priest needs. I doubt that anyone uses it at all. Maybe it should be redone into something else. Or maybe you could give it a dexterity bonus instead?
Searing light is an interesting talent to some extent. You can make it trigger not from magic shouts, but from a certain chance at any attack, magical or physical. Thus giving the priest more maneuvers.
Purifying flames is now a bonus to holy talents, which looks silly. It could be redone by giving the priest a magical bonus to melee (and ranged?) attacks.
Enlighten and Chastise - now they are quite suitable for what I see, but perhaps they should be reviewed and balanced. Enlighten is triggered not only by magical attacks.
Force of Will - I don't even know, it seems to be normal if the critical chance bonus is triggered by the damage of the magic bonus to melee attacks. satisfied with Purifying flames.
Maybe something else, show me your ideas.
I'll turn to the "true nerds" right away, if you want boring vanilla talents, then you shouldn't write your stupid comments here trying to make fun of me or other people with interesting ideas. I'm just offering fresh ideas that can make the game a little more interesting and diverse.