ben_danger said:what if ghost yoda was in bens hut too? wouldnt make much sence, but if the dialogue from the beginning was cut/changed. additional dialogue could be used later if he appears as a ghost. alternatively he could just appear silently.
I think Luke would just associate that place with Ben and seeing Yoda's ghost so early would detract from his appearence at the end with his saved father.
In a way taking Ben away from Dagobah helps affirm Yoda's link to his home too.
In ESB we heard Ben's voice and saw him for a few seconds but really Dagobah is Yoda's domain so having Ben wandering around it seems a bit weird (on Hoth Ben could just float for a few seconds).