There are really two choices I can think of here: Xenosaga HD and Xenoblade X2. 

For me personally, while I would love to see Monolith Soft retcon the entire Xenosaga series and complete the masterpiece they originally had planned, I just don't see Nintendo looking at that as a viable move to make. Not only that, but to get Monolith Soft back on board would ultimately need to halt production on their currently running series, Xenoblade X. So, if it IS a choice I have to make than I would rather see Xenoblade X2.

I've already played the Xenosaga series (for better and worse) and while there was a LOT of good in the series, the Xenoblade series just has so much more potential that I would rather not have to wait years more to experience. Personally I say let Bamco do a port of the existing material maybe work with Takahashi to add a few new things. Even if Bamco made it an exclusive for another console, I think it'd personally be a better option. 

But with that said, I know there are quite a bit of people who weren't exactly thrilled with Xenoblade X. So I'm trying to get a general feel for what people would rather see. 

Xenoblade 3.
Another big open world like X.

Neither. Monolith software is nintendo, I highly doubt theyre bothering making xenosaga hd for Nintendo only, in fact I highly doubt theyre making it at all lol.
As for xenoblade, I can actually see nintendo putting them to work on something else. The xenoblades were big undertakings that didn't light the charts on fire. I'd imagine nintendo would like something that costs less and sells at least the same if not better

What if my choice is Xenoblade Chronicles 2??
Havent played XCX but if there marketing of it was anything to go buy it was a step in the wrong direction.

Honestly, I want to see more of what this is...

when/where was that posted ?

This was posted a LONG time ago on there official website when they were hiring for 3DS developers.

Something new. The lead developer of the Xeno series doesn't like to stay on the same thing for too long. We'll most likely see something new and different.

didn't somebody at the head of Monolith that they wanted to make a more "western-like" game ? I can't remember if it was refered to X or to a totally new project...

What bigtakilla said... xD I wish this was made into a game... This concept looked interesting.