Here's another cautionary example besides the disaster that was X:Rebirth.
Does anyone here remember what happened with the Silent Hunter series? For years, players pleaded with the devs to let us walk around inside the submarine, interacting with crew members, helping with engine repairs and damage control instead of having a simple menu-based command interface.
Well, we got that in Silent Hunter 5 and it killed the series.
The one good thing about it was that yes, we could finally move around inside a 3D environment from one end of the sub to the other. But the crew interaction was badly designed, the controls were clumsy, and so much time and effort was spent on that aspect that the rest of the game was a horrible, broken mess. Silent Hunter 5 would have been a far better product if they had ignored what the players wanted for full submarine interior interaction, and focused more on the rest of the game.
That can't happen to ED, at least to the same extent, because we already have a core game engine that works without the walking around stuff. And since it will be sold as an expansion, it shouldn't be possible to harm the core game the way SH5's focus on interiors did. But it's still another object lesson in what can go wrong, especially with smaller studios and limited budgets.