Xenoblade Chronicles released on the Wii in 2011, and it received critical acclaim. The pseudo open-world RPG blew expectations out of the water and proved itself to be more than just a Monster Hunter/Final Fantasy clone.
A follow-up wasn't expected when it appeared back in January when the Switch was revealed, especially considering Xenoblade Chronicles X only released two years ago on Wii U. To say the least, it was a nice surprise.
Xenoblade Chronicles 2 was also a sight for sore eyes because it was another huge open-world title for gamers to look forward to after Breath of the Wild. Beyond Zelda, there haven't been a lot of big titles for Switch gamers to sink their teeth into, but Xenoblade can give them exactly that.
I would expect Xenoblade Chronicles 2 to sell very well on the Switch, so Nintendo will want to heavily promote it. The game is due for release sometime this year, so we should be seeing a lot more of it at E3.