Composing music is like taking photographs. As the time between a camera shutter opening and closing dictates the sharpness of the image, so does the time a recording is in flux dictate its relevance to the composer's ever changing tastes and circumstances. There is a tradeoff between perfecting the record, which takes time, and crystallizing it as an artifact of the moment.
Of course, it's not every composer's goal to capture moments in time, and it's not to say every piece of music that's taken a long time to create winds up unfocused. After all, long photographic exposures can reveal subtle details. But it takes great care, like high tech telescopes that track the stars, to get a clear image.
Alternate Worlds is shaping up to be a snapshot compared to the long exposure of Sixteen Worlds.
They're photos of the same subject taken a year apart, but it's surprising how different they feel. If the photography metaphors don't work for you, consider two acting companies performing Waiting For Godot. The words, themes, and characters are the same in each case. Yet the people involved, their interpretation, and the quality of the popcorn couldn't be more different.