Here are some ideas to improve the Charmer an charmer's Call (ignoring some "Summoner Skill" effects):
1: Buff.
1.1: Increase his physical damage.
If the player has 100 physical damage, make the wolf do 150.
If the player has 500, make the wolf do 750.
1.2: Increase his attack speed.
Let's say the wolf's current attack speed is 3.0, it could decrease to 2.0.
1.3: Increase his defense and/or life per player level.
If you are a healer/magical damage healer, the dog is useless. With this buff, it makes it more tanky.
2: Rework.
2.1: Wolf Rework: Focusing on Your Target.
This skill needed it from the start. Even if they added this to the "Summoner Skill", it was necessary in the Call itself.
2.2: Prism Rework: Commander
Give it the same effect as the "Summoner Skill" of controlling the wolf.
2.3: Crow Rework: Heal and Attack
A very simple rework. When you cast the crow in the wolf, make it attacks and heal.
2.4: Equipment Rework: Spears and Two-handed Maces.
Spears and 2h maces are weapons with high physical damage and a little magical damage. It can help the wolf and the passive's damage and still can heal, do magical damage, etc.