Read the comments of the Xeno creator on the history of the series and it'll make sense why the would be a cliffhanger. The whole Xeno series was created to be a 6 part series like the original Star Wars, Xenogears was part 5 apparently, then the who fall out with Square happened but he still had the rights to any other part of the series provided he made changes to it that it wouldn't infringe on Xenogears.
Xenosaga was created and is apparently part 2 of his series, how ever Namco stepped and decided they wanted to write the whole saga instead of Monolith leading to the second road bump the series ran into. Xenoblade was the turning point as he was expecting Nintendo to step in and cut content like Square and Namco did instead Nintendo told him the opposite and to take his time and only release it when he was happy with the final product.
Expect cliffhangers as apparently he has a connected universe in mind even if the cast and setting change.