A troubling pattern with a lot of re-releases/remasters of classic titles is that publishers are either unable to get voice actors to return or don't even bother to make the effort. We saw this with Tales of Vesperia: Definitive Edition and even the Silent Hill HD Collection, to an extent. Thankfully, Nintendo won't be making the same mistake with Xenoblade Chronicles: Definitive Edition.
In a video published by RogersBase, Nintendo Treehouse's Robert Watters confirmed that the original English voice actors for both Shulk and Melia will return in Future Connected, the epilogue chapter of this Switch port. As can be seen in the video below (starting around 1:36), Watters states, "They got the voice cast back, even Melia. She's returned."
Further on in the video, a sample of the voice acting can be seen in a preview for the epilogue. It isn't the most exciting bit of acting, but it does clearly show off the returning cast. If you'd rather avoid spoilers, don't watch past the 10-minute mark.
As for details more related to gameplay, players will be able to sort of customize the look of their characters. In the original Xenoblade Chronicles, swapping armor would completely change the design of characters in cutscenes. Now, any piece of unlocked equipment can have its aesthetics changed to suit your needs.
If you happen to play through the epilogue first, you can even take the new armor sets back into the original campaign. It's not exactly clear if that means different armor stats or not, but it's a neat way to reward collecting each piece of gear. There's a lot in Xenoblade, so that should make completionists happy.
From everything we've learned about Definitive Edition, it really seems to be living up to its moniker. The lack of amiibo support is still quite odd, but I can deal with that when substantial gameplay has been added. It's also a nice treat for fans of the English VO to learn their favorite actors are returning.
With any luck, the success of Xenoblade Chronicles: Definitive Edition could result in a port for the Wii U exclusive Xenoblade Chronicles X. That would be nice.
Source: YouTube