The scale resulted in some warts to be sure, but the tradeoff being that they created some of the most memorable worlds in gaming imo. More than worth it.
The big issue with Xenoblade X is the focus on sidequests over main story. They just don't have the budget/team size/whatever to flesh out the mountains of sidequests they attempted in X, and what was left of the main story was a mess. The cutscene quality dramatically deteriorated as a result of trying to do so much. Just create a nice epic world with a strong main story Monolithsoft, I know you can do it. Seems like that's the direction they're gonna go in anyways so I'm ready.
There are some things I hope they keep from X, like the traversal options. Exploration was much more interesting in X.