I honestly hope they do because if you may remember before the game even came out there was a lot of worry that you would have only island per switch and it was a "rumor" at the time. Then when the game came out it was confirmed that the rumor that island was only one per switch was true. I remember when the game was getting SO MANY review bombs because people were outraged that it was a one island per switch.
I can see why people were upset because when its only one island per switch there is no way to share with your families. Which is bad because suppose if someone comes on your switch and messes up your island without you noticing. Also You can add users to your island but you only get their homes on their island yet you cannot do most things that the main user can do like Move Buildings around. Even the co-op is still poorly developed because the leader has all the control but the follower doesn't
This is probably the biggest issue with this game and probably the main reasons why its been heavily criticized for the longest time. I am not sure what Nintendo would do to fix this but they would have to really listen to the community because many people don't want to have to restart their island just to make a new one. The best thing I can say is we will have to wait and see what happens because knowing Nintendo they have their own plans of what the game is going to be like in the future and the chances if they will listen is very unlikely. I hope I'm wrong but only time will tell.