Summoner classes like Bokor / Sorcerer / Necro are not future proof and are fated to die at rank 8.
Please make sure to add something like a % of the monster max hp as extra damage.
Follow the example:
Sorcerer “Summoning”:
For normal monsters: 3% of monster max hp as extra damage
For elite monsters: 2% of monster max hp as extra damage
For bosses: 0.5% of monster max hp as extra damage
Do the same for 
and 
But weaker.
For normal monsters: 2% of monster max hp as extra damage
For elite monsters: 1% of monster max hp as extra damage
For bosses: 0.25% of monster max hp as extra damage
A little hand to necromancers:
and
For normal monsters: 3% of monster max hp as extra damage
For elite monsters: 2% of monster max hp as extra damage
For bosses: 0.5% of monster max hp as extra damage
and
For normal monsters: 2% of monster max hp as extra damage
For elite monsters: 1% of monster max hp as extra damage
For bosses: 0.1% of monster max hp as extra damage
And for Bokor:
For normal monsters: 1% of monster max hp as extra damage
For elite monsters: 0.5% of monster max hp as extra damage
For bosses: 0.05% of monster max hp as extra damage
To finish, just to secure all summonings survivability: Add 15% of total damage as life leech to all summonings.