I've really only tried a little and I think I'm going to leave it until after I've finished xenoblade (I'm level 74 I think I'm somewhere near the end... maybe) and played through fallout 4.
On the surface X is disappointing when compared to xenoblade.
The conversations seems wooden and filled with pauses. The presence of a silent protagonist really doesn't help and I think in this case that was a design mistake.
The music does jar with me and I thought I'd be ok with it.
The off tv play seems like an after thought and as someone who is playing xenoblade entirely in off tv mode I can say that Xenoblade has got far better off tv support. It has larger clearer fonts and the map is mapped to the convenient minus button. I prefer the button mapping in xenoblade but that might be because I'm used to it. I also prefer the menu system, again that could be because I'm used to it - along with the larger clearer fonts which work well in off tv mode and with my so so eyesight.
I haven't played enough to give more negative crit. But what I liked about X was the sense of scale, the outdoor visuals and strange life forms and their more realistic behavior such as feeding and sleeping.
It's more open and less plot orientated than xenoblade and I feel it is to dissimilar to warrant the xenoblade name. It suffers from comparisons which is a shame.
I've not yet finished Xenoblade, and it's not perfect, but Xenoblade is likely one of, if not the best, jrpgs I've ever played. Expecting X to live up to that, especially when it's trying to be something very different, is too much.