Unique Map Events
What I mean by that is for example when you repair two specific gens on the Silent Hill map it opens the tower which has a chest in it.
But take that and make it more involved. I'll share some ideas, First on the Huntress's map there could be a wolf searching for her cub that will run away when you get close. However you can find the cub in someplace and bring it to Her which may give you blood points or she may protect you from the killer once before leaving. Another could be runes scattered around the map that go into a slot somewhere, once you found all the runes and put them in the right places you could make the weather change or make the map's objects change. Now both killer and survivor could do any of these.
It might not be helpful or that good but it would still be cool and worth doing when you can.
Comments
This is interesting, but I think it should be limited to things like weather changes or something like rotating loops. Imagine being able to hold lever or push buttons and close vaults or open walls up to run through...