The meaning of a story is in its ending. That's why we don't like the deus ex machina, since it violates everything about the story up until that poiint. It's a cheap way out.
The failure to provide an ending may be a gimmick that works once, as in "The Lady and the Tiger." But for the creators of a years-long series - which took a year off to go find itself, remember - to fail to provide an ending, is artistically a similar act of cowardice.