I have only played through the first opening hours of Torna, but it seems like it expands on Addam and Gin's story in the past. When I first played Xeno2 back in 2017, I always thought it was odd how they never went into Addam's story at all and what Gin's whole deal was with the red haired girl. This game seems to address all those missing details. I mean, they were sorta there in the main game, but not nearly enough to give a full picture. The Torna group had a lot of characters that just didn't get enough time in the oven, so I hope this side game rectifies that.
I dunno how I feel about them ripping the story up and putting it into a separate game. I hope they don't do that for Xenoblade 3, or at the least, let the story feel complete in the vanilla game and if they want to add more story do it as a sequel DLC or side game like Xenoblade DE.