The basic tech is meshed together. That's a fact. Ship Interiors, Cities, Planets work.
Rubbish, you talk as if the game is 'just missing x, y or z game loop and it would all be ok'. The physics grid(s) they are using are screwed, instancing is screwed - you aint getting any epic Idris-offs anytime soon buddy - as well as a host of other things. AI - screwed....want me to go on?
Those things don't work if lifts, ramps, ships and misplaced rocks can kill you, they don't work if your inventory is a lottery, they don't work if the AI dislocates their spine or sinks into the floor....want me to go on?