It won't be "difficult", it will be impossible. Even with a huge intimidate score and some nice melee threat enhancement, your buffer will be under 300. Any slightly dps-oriented character can do more than 300 damage in 15s.
You just killed the good old intimidate+shield-blocking, and ruined my next character idea... Good job removing options from the players (it was nice to have a way to contribute to the party that was not directly related to inflicting damage).