There's a difference between shitty and disappointing games. I wouldn't credit Fallout 4 as an unplayable pile of shit. I believe that, if the engine was used under the right kind of developmental lead, it could potentially be a stark improvement over New Vegas. The main problem with Fallout 4 is the lost potential. The people in charge of its development either chose to actively ignore the strides Obsidian took in NV or failed to emulate them. And while it's wonderful to give someone the benefit of the doubt every once in awhile, we're talking about a major AAA development studio. These guys should know what the they're doing.