Honestly it is more than fair feedback, it's a conversation we've had a few times recently.
That is that essentially we introduce various different mechanics like venom, then make anything in or close to the 'boss' category out of fear it's abused. (venom it and hide kind of thing). I'd never want a challenge boss like Jad for example to be beaten that way - simply venom and then hide around the otherside of the rock - so it'd never be gone everywhere.
I cannot promise we'll go back and review all the stuff in that list but it may be something we do at some point. Going forward I believe we'll try and avoid doing this so much. Tormented demons for example do take venom damage.