An optimal option :) and suitable for all situations. The only question is, for which races will this be available? Definitely not for Demons or Necromancers.
The advanced skill "Monster Taming" has a 35% chance of failing to tame a monster (boss), and the monster's stats are reduced to 40%.
The expert skill "Monster Taming" has a 25% chance of failing to tame a monster (boss), and the monster's stats are reduced to 50%.
How does this idea sound?