The following info comes from a Joystiq interview with series creator Katsuya Eguchi and Director Aya Kyogoku...

- with the original Animal Crossing, the team was less focused on making a game and more focused on making a second place to live
- the devs say it's difficult to build a universally welcoming foundation for everyone to find their second home
- this challenge was kept in mind when work began on New Leaf
- the dev team on New Leaf encompassed members from different age groups and walks of life
- the direct interaction with other characters and real-life people is key to Animal Crossing
- promotional items offered at real-world physical locations are meant to encourage that sense of sharing from other players
- if many people head to a store in search of an item, Kyogoku hopes that they'll StreetPass with one another during their visit
- StreetPass is viewed as an incentive for players to take Animal Crossing with them in their daily lives
- tying the availability of items and events to particular moments in a year helps reinforce the idea that life in Animal Crossing moves on, with or without you
- maintaining the calendar's influence is part of why the series has stayed away from implementing microtransactions
- special items are more about rewarding event attendance and less about filling out a checklist
- Eguchi hopes to reach regions he feels are untapped with future AC games, such as Australia
- he also looks forward to utilizing the features in Nintendo's hardware to show off new elements of life in Animal Crossing's world