Quote from KoishiKomeiji
It's not finished because it's in a snapshot. simple as that.
As always,this is correct.
But the only thing that will make the adventure mode be fixed would be : Be able to use stuff that we get from chests.
And not only torches or levers, even blocks, but only those obtained through chests made by the map creator.
Of course, that will not make every adventure map compatible, but since now map makers will have to stick to this " format " if they want their map to work with the adventure mode.