To answer my own question based on what I can recall about this game (and feel free to correct as needed):
- Dream Emporium allows you to upload a copy of your town for others to visit online even when you're not around, at NO risk to your town. They can purchase/collect items from your town before returning to their own. You can likewise tour uploaded towns yourself.
- Tom Nook runs a neighborhood of model homes, containing replicas of homes of other users, both local and online (StreetPass, SpotPass), in which you can buy copies of any given piece of furniture, etc, including pieces with customized patterns.
- The ability to create patterns that can then be turned into QR codes for instant sharing with others -- no need to painstakingly recreate patterns pixel by pixel. Also, you can place patterns on virtually anything, including individual pieces of furniture, and in the end, you can take screenshots of anything, anywhere, anytime, meaning you can share shots of your custom home and town.
- As mayor you can collect community contributions to fund benches, bridges, fountains, playscapes, windmills, lighthouses, totem poles, archways, igloos, lawn ornaments and more. You even hold ribbon-cutting ceremonies for them, and have a secretary that can accompany you across town, and your own office, as well.
- Homes and the all-new camping tents can be individually placed; the exterior of homes are also now fully customizable, right down to the architectural style and hedges. Also, your basement can be fully customized like any other room now, and you still have multiple rooms on the main floor of the house.
- You can go on a picnic, eat popsicles outside, walk about town drinking coffee, and on that note, you can work part-time as a barista, and at night, you can go clubbing at the disco, one of many shops in the dedicated shopping plaza across the train tracks, which also includes a dedicated gardening shop, shoes/socks/boots shop, and more. Isn't there even someone you can hire to pluck weeds for you?
- You can wear individual pieces of clothing on individual parts of your body, including swimsuits, in which you can go swimming and snorkeling down by the beach, diving for treasure or collecting fish. There is also an island to sail to with minigames to play with up to four players, locally or online, including timed hedge maze races and whack-a-mole.
- Something to the effect of 1.5X the number of items in City Folk are available in New Leaf. And again, all of the furniture can be customized by way of the new alpaca characters.
Hmm, what am I missing?