I have some ideas for Thorin III. and larger differences between his two versions.
I think it is a pity that both his versions are very similar. Maybe young Thorin III. can be stubborn and more aggressive.
Iron Hills version (Thorin III.):He gets a new unique two-handed weapon:
Level 1: Runes (same as now)
Level 1: Dain's heritage (same as now)
Level 5: Retribution: Thorin wants to avenge their fallen friends. He is angry to enemy hero and try to kill him. Enemy hero dealing damage and he can't move for 5 seconds.
Level 10: Stubborn dwarf: Thorin plunges into battle with enthusiasm and destroys everything in his path. For 20 seconds he deals +75% more damage.
Erebor version (Thorin Stonehelm):Level 1: Runes (same as now)
Level 1: Prince under the Mountain: His ability "Dain's heritage" gets a new name.
Level 5: Righteous Heap (same as now)
Level 10: Stonehelm: His ability "Iron Determination" gets a new name. This ability is the same but also Thorin gets +1000 health points and selected hero gets +500 health points.
What do you think about this?