/signed.
When the devs were asked why they gave these immunities to red named bosses, the only answer they ever gave was: ifplayers can make all the preparation to get all the right immunity items to prepare for specific fights, the best of the monsters (rednamed) should be able to do so too.
Following that logic, players should have long ago been able to find immunity items for trip, stunning blow, etc. When asked about that, the devs have remained silent. They refuse to follow their own logic through (with one small exception: we now have the acrobat enhancement available to rogues, a very exclusive and arguably not very useful line).