The following comes from a Polygon interview with Kenta Nakanishi, a director on Shadows of Valentia...
“After making Fire Emblem Fates, talking with the developers at Intelligent Systems, we were hoping to integrate things that we couldn’t do with Fire Emblem Fates on the 3DS platform.
When I played it as a youth, the story and the characters weren’t as memorable. Back then [in 1992], the reason why there wasn’t too much depth to the story was because a lot of the story element was explained in the manual.
We did consider adding things like My Unit and the Avatar [personalization options from the previous 3DS Fire Emblem games], but we really wanted to focus on Alm and Celica.
This is only just what we have seen in Japan, but we definitely heard people that have played the original fire emblem garden were nostalgic [when playing] this remake, and also that new players were coming in and saying it’s a very new and fresh take on Fire Emblem. We believe that it was successful in what were we trying to achieve.”