If it would be released next year, then that means they only had 1 year to work on it unless they've started development before 2017. If anything, I'd assume it will be out by 2019 or 2020.
Given the success of
Animal Crossing: New Leaf and that Nintendo begins development on the next main entry in series like Mario and Zelda
as soon as the previous title is completed, it's extremely unlikely work on the next Animal Crossing, even if just early dev. and prototyping work, didn't start
as soon as Animal Crossing: New Leaf was done. Plus, by working on multiple games, Nintendo can
recycle assets. For example,
Animal Crossing: Amiibo Festival has the series first HD assets, and
Animal Crossing Happy Home Designer has a number of new gameplay systems that could be implemented in the next game. These things can be reused in a future title, and Nintendo gets to put out
more games in the interim.
Nintendo
has the resources to do this as they do with even smaller series than Animal Crossing. Animal Crossing has become one of Nintendo's
best selling franchises eclipsed only by Mario and Pokemon. The series outperforms Monster Hunter, Kirby, Fire Emblem, and even Zelda. With that said, it’s worth looking at what Nintendo has said about upcoming Animal Crossing games.
Back in 2013 series
creator/director Katsuya Eguchi said to Gamesradar they were already working on the
next game, but said it didn't have a "concrete direction yet" and weren't sure what hardware they would develop for. Most at the time assumed it would be a Wii U game even though he wouldn't commit to Wii U when asked directly. (It's worth noting he had no involvement with
Animal Crossing: Amiibo Festival). Then in 2014 Eguchi said to Polygon that Animal Crossing is “best suited for a
portable device” and that "whether it's the Wii U or a
future hardware, it's important to think about what environment the player will be in."
Also, in the same Polygon interview
co-director Aya Kyogoku said she
doesn’t think Animal Crossing would work on smart-devices, but doing "something that
supports playing on a Nintendo device, something that relates to the information content of the game, something that brings players back to the main game […] as a catalyst to get players back into the game, it's something we might look into." She notes "to have
reminders […] there's something going on in the world of Animal Crossing, is something I think is great." (This is before Nintendo had officially announced mobile apps or the Animal Crossing app.)
Then we have this statement from
Nintendo President Tatsumi Kimishima from last year:
We are currently developing a new application for smart devices based on the characters and world of Animal Crossing.
As I mentioned before, the Animal Crossing series for dedicated video game systems is well-loved for its long-term playability, so we want to offer a connection between the smart device application and the world of Animal Crossing on dedicated video game systems. This will make it even more fun to play in both ways, while offering a new style of play for smart devices.
We are developing this application to provide consumers with strong value suitable to smart devices while also generating synergy with our dedicated video game system business, as this is one of the goals of our smart device business.
Piecing this and other information together, it seems clear Nintendo plans to create an Animal Crossing app that will connect to the main game in a meaningful way but will not offer the same gameplay experience of the main games (like their other apps). I suspect
Animal Crossing: New Leaf will get an update supporting a connection to this app somehow. However, I think what Nintendo did with Pok?mon and now Fire Emblem is what they will aim for with Animal Crossing, and new titles are a vital part of that. While
Pok?mon Go did increase sales for older titles,
it was Pok?mon Sun & Moon that got the real benefit. The older games had already sold to a great many people. It took something new to bring in real revenue.
Animal Crossing will be in the exact same situation. Therefore, even if it’s for some reason not the next main entry in the series, I think we will get another Animal Crossing game
within a year of the app’s release. And I don’t think it makes much sense for that game to go to 3DS, especially if it’s a main entry, as 3DS is approaching saturation and already has two great Animal Crossing games to offer
new 3DS buyers. I think 2019 is the
absolute latest we will see the next Animal Crossing and it will release for the
Nintendo Switch.