Why? because it tries to fix something that isn't the problem.
Boss Camping is nothing, you have every information to counteract them already. just get 3 clues and you are ready for all possible dangers.
why would I need Whispers to tell there's guys at boss lair? of course there's people up there, what's the point of bosses otherwise?Boss Camping alone is not that bad of a behavior, they are at some degree playing the objective. they are there to fight for prize.
the real problem is, they are AFRAID TO COME OUT: because no matter what you do there will be this one duo carrying two long range rifles and refuse to take any risks.these long range sniper guys, they don't play objectives, instead let others do all the tasks while they are sitting at their superior position. when someone grabs bounty because no sane person is willing to waste 40 mins of their life, it's their Mosin's time to shine.
THIS is what needs fixing, good gameplay design is all about FORCING REACTIONS, and we have zero tools to do that against this long range sniper guys. they will only play the game when they know for sure they will win the fight and otherwise they will be sitting at their position, doing absolutely nothing.