The one thing said in that video I believe: they changed it because they got sick of everyone reporting everyone for cheating.

I think the buffs to the strike playlist drops more than make up for the loot cave nerf.

Well to be accurate they stated that the rate of good loot drops were low. I never got anything good out of the loot cave. But besides that it sounds like the real reason was not that the loot drop was low but because of the idiots who considered it to be "cheating" and did not want people to play the game the way they wanted to play it but instead were attempting to force players to conform to their belief that doing this is the same as wallhacking in a PVP FPS game. So in the end it was the mass of people reporting eachother and others inappropriately attempting to "police" a perfectly legitimate action other players were doing that made them change this. Honestly I think Bungie is foolish for not telling people this up front. It would be a lot easier to understand if your reason is we are being swamped with people reporting each other either for being douche bags or acting like douche bags and reporting players playing how they wish.