That's exactly why Bethesda is worth many millions right now, that they always change the formula inbetween games, and its why they piss off that extremely small section of gamers who cannot handle change and demand that everything be the same.
If they were not commited to changing things to make a better game we would never have got a game like Morrowind, and the company would have never got enough money to buy the Fallout IP.
Think about it. Daggerfall was all about randomly generated everything, and that would not come back in any way for many years. In Daggerfall a standard quest may assign you to kill a orc chieftan, and you would fast travel and land at a random dungeon that was generated and not designed, and would fight anywhere from bears, bats, rats, to other orcs before barreling down to the heart of the dungeon and taking out the orc chieftan. That being if you were lucky and every had not glitched out to the point where the chieftan was behind a inaccesible part of the dungeon, or had flat out spawned outside the world into the void.
Does that sound anything like Morrowind? In Morrowind the world is hand-designed, and full of detail, with designers making dungeons instead of computer algorithims. Some things had remained, like the dice roll combat and text-based dialogue, but the world was now populated with actual characters, and not random people who had every part of themselves generated when you went into town. And yes, back in 2002 the exact same people said that all of these changes were "Dumbing down", "streamlining", or that it was "Console trash".
This has repeated itself every time there's been a new release, with the exception of New Vegas. in Oblivion there was no dice roll combat, and people were fully voiced, and had the radiant AI that was so hyped. in Fallout 3, there was VATS, and a huge focus on a small quantity of high quality quests. And again in Skyrim, the quest system from Daggerfall made a small comeback, with huge experimentation on non-linear and non-scripted reactivity.
The games will change from release to release, and Fallout 4 will be no different. It may be a big or a small change, but there will be changes nontheless. People act as if Bethesda has been stamping out the same game every single time since 1994, but the truth is the complete opposite.