A lot of that can be fixed with signposting. For example, there is someone right outside Caed Nua who mentions that it's scary in there. Maybe add a little piece of dialogue which triggers based off party Health, advising maybe they should rest up first.
Now if players just skip all dialogue, I feel they deserve what they get.
This is probably one of the best ways to create a good encounter design and mitigate metagaming. I have been advertising this approach since ages on beta forums: Just trigger quests based on dialogue comprehension. Let people decide for themselves by reading stuff where a quest is, how to solve it. That way metagaming only helps as far as replaying the entire game and not an encounter.
When will people learn this...
DX did it amazingly well. So did the first witcher game a bit . Best ever was of course morrowind.