They fixed the loot caves because they didn't want people just shooting into a cave openning. That had nothing to do with Loot, that was more about Farming. For the record I didn't agree with that patch, but I understand why they did it. As far as quantity goes, I get plenty of engrams, I got a Vault full of Legendaries and Exotics, as well as a dozen or so on each character. That is just luck though.