Lessons Learned for Fallout 4

MTV Multiplayer continues to feed us tidbits from their email interview with Bethesda, this time discussing the biggest lesson learned from Fallout 3 for Fallout 4.
As part of an e-mail interview with (Fallout 3″ executive producer Todd Howard, we asked him what he's learned from making (Fallout 3″ that will carry into (Fallout 4.) His answer was short, sweet and told us nothing.
Really? I would think there'd be bigger things that went wrong with Fallout 3, "in hindsight".